Monday, September 21, 2020

Did Global Warming Play A Significant Role in the Recent Northwest Wildfires?


A number of groups and individuals are claiming that the recent major wildfires in the Pacific Northwest are predominantly or significantly the result of climate change produced by increasing greenhouse gases.

In fact, many have called these conflagrations "climate fires."    Did global warming (a.k.a. climate change) have a significant impact on the Northwest wildfires of the past few weeks?

Consider the key fires in the Northwest U.S. this month: the huge, rapidly expanding fires on the western slopes of the Oregon Cascades. 

The fires that not only burned hundreds of thousands of acres, but produced most of the smoke that engulfed the region for over a week.  As I will demonstrate, the catastrophic Oregon Cascade fires of the past weeks were forced by strong easterly winds, and such winds may well weaken under global warming.  And I will show that the weather of the past summer was relatively normal.

Thus, although global warming will undoubtedly produce substantial changes in our climate in the future, the impacts of global warming on the recent Oregon fires were probably quite small.

Smoke reaches Portland.  Image by Tedder.

I should note that BEFORE the recent fires I had been working on research and a paper on the meteorology of western Cascade fires and have a NSF grant to examine California wildfires.  Furthermore, I have worked closely with the Washington State Departments of Ecology and Natural Resources, as well as the USDA Forest Service, on Northwest wildfire meteorology and prediction. 

Fires on the Western Slopes of the Oregon Cascades and their Historical Context

A series of major fires exploded on September 7-8, 2020, ranging from the Big Hollow Fire northeast of Portland, the Riverside, Beach Creek and Lionshead Fires east of Salem, the Holiday Fire near Eugene, and the Archie Creek, South Obenchain and other fires to the south.  Several of the western Cascade Range fires, which have spread over more than 350,000 acres, had been initiated by lightning in mid-August, smoldering until strong easterly winds caused rapid expansion.


Fires along the western slopes of the Cascades are infrequent but regular, with research studies using proxy information (such as charcoal remnants in the soil and tree ring/scaring data) finding stand-killing fires occur roughly every 250 years (e.g. this reference).   Importantly, during the past century, few major fires has burned over western slopes of the Oregon Cascades, with the most prominent being the Yacolt Burn (1902, 500,000 acres) and the Eagle Creek Fire (2017, 50,000 acres), both near the Columbia Gorge east of Portland.  Interestingly, there has been far more fire activity over the coastal mountains of Oregon than along the western slopes of the Cascades during the past 120 years.  Thus, many of the recent fires along the western Cascades slopes were burning across terrain that had not experienced major fires in over a century.

Fires and their sizes since 1900 over Oregon. Image created by Lynne Palombo of the Oregonian.

Strong Easterly Winds Are Necessary for Major Wildfires on the Western Slopes of the Cascades

It has long been known that major wildfires over the western slopes of the Oregon Cascades have been limited to periods of sustained, strong easterly winds (from the east).   To quote a classic paper (FREQUENCY of DRY EAST WINDS OVER NORTHWEST OREGON and SOUTHWEST WASHINGTON, Cramer 1957):

The history of forest conflagrations in the Northwest is, for the most part, a history of the simultaneous occurrence of small fires and severe east winds.

Most of the biggest fires along the crest and western slopes of the Oregon Cascades started with small fires, either natural or human-initiated, which without winds would smolder or very slowly grow.  But add strong easterly winds and they can explode as seen on September 8th.

As part of my research, I determined every major fire on western side of the Oregon and Washington Cascades since 1900, and then examined the meteorology of each using observations, newspaper accounts, and the reanalysis grids (gridded analyses based on observation that go back to the 1860s).   EVERY such major fire, without exception, was associated with strong easterly winds.

The Tillamook Burn included a series of fires starting in 1933 that torched over 350,000 acres

Why are strong easterly winds required for the megafires on the Oregon western slopes?   

First, easterly winds tend to be very dry and usually warm, which helps desiccate surface fuels.  Westerly winds off the ocean are generally cool and moist, not only bringing high relative humidity but often moving fog and low clouds over the western Cascade slopes, both negatives for fires.  Easterly winds are from the dry, warm interior of the continent, and as the air sinks along the western slopes it is compressed and thus warmed as it moves to lower elevations (where pressure is higher).  Because of the warming, the relatively humidity plummets as the air sinks.   Very favorable for fires.

Furthermore, strong easterly winds not only facilitate warming and drying but also provides oxygen to fires, allowing them to expand rapidly.  In addition, strong winds push superheated gases ahead of fires (which helps then move quickly) and strong winds loft firebrands and embers that produce spot fires ahead of the main fire line.

The bottom line:  strong easterly winds are very important for starting fires on the western Cascade slopes, which are typically resistant to fire because of their relatively moist surfaces and extensive shading.
So the questions you must be asking at this point:   were the recent Oregon wildfires associated with strong easterly winds?   Is there a climate connection with such winds? Are easterly winds increasing as the earth has warmed the last 40 years?   And do climate models suggest that global warming will increase easterly winds over the western slopes of the Cascades?

The answer to the first question is an emphatic YES.  The September event was associated with powerful and sustained easterly winds  over the Cascades, with some gusts reaching 50-70 mph (see map below of maximum gusts on September 8th in mph).  Enough to cause large numbers of power outages in Oregon.

Maximum winds on September 8 over western Oregon

The balloon-launched sounding at Salem, Oregon for 5 AM Tuesday, September 8th showed strong northeasterly and easterly winds though the entire lower atmosphere (shown up to roughly 10,000 ft in the figure).

Bottom line:  strong easterly winds occurred over the lower atmosphere of western Oregon from late on September 7, peaking on Sept 8th, and continuing in weakened form during the event.

Strong easterly winds are relatively unusual during the summer over western Oregon   So how unusual was this easterly flow event?   It turns out EXTREMELY unusual. 


To examine this, I searched gridded weather data (the NCAR-NCEP reanalysis) for a grid point on the western slopes of the Oregon Cascades.  Specifically, I examined the strength of the daily average zonal (east-west wind), looking for the days of strongest easterly wind.  For example, I checked surface wind (10-m above the surface) from 1950 to today for July through September--the relevant months-- and found the top ten cases.

The grid point I used for this analysis

The results show that September 8 had the strongest easterly surface wind over the period examined (more negative means more easterly), substantially exceeding second place (Sept 17, 1971). And Sept. 9 was also on the list.  Only one other multi-day sequence was on the list (Sept. 16-18, 1971) and there were major fires that period as well.


Results of  one of my analyses

What produced this record-breaking easterly wind event starting Sept. 7th?  An extraordinarily area of COLD temperatures and associated high pressure area that moved southeastward to the east of our region, coupled with an unusual low pressure offshore.

Below is the pressure analysis at 5 AM on Sept. 8, with the solid lines indicating pressure (isobars) and the colors indicating differences from normal).  Strong high pressure was over Montana, while a trough of low pressure was along the coast.  Between these two features there was a large difference in pressure.  The colors indicate that the high pressure, centered in Montana was very unusual, with the difference from normal (the anomaly) being very unusual (4-5 standard deviations from normal for those of you knowledgeable about statistics)



Looking at winds at 925 hPa (about 2500 ft above sea level) at the same time, the strongest winds were over western Oregon, reaching over 6 standard deviations from normal.  Unprecedented conditions for this date.


Let me underline something I noted above: the anomalous high pressure was associated with very unusually cold air, air that would bring snow to Denver in the subsequent day.

Is there a trend of more easterly winds over Northwest Washington in the operational record?   

If one is interested in climate change, one MUST look at trends over time. Below is a plot of the top 10 cases of easterly wind at the grid point noted above--there is no evidence of an upward trend over time.    So with increasing temperatures as the planet has warmed, there is no apparent increase of easterly wind occurrence over the region.  This is a serious strike against the global warming/wildfire contention.

But let's not stop there.  My group, in concert with Professor Eric Salathe of UW Bothell, are running a high-resolution climate model forced by increasing greenhouse gases--probably the most sophisticated local climate modeling in the country.  And we are doing this with an ensemble of many ultra-high resolution climate runs.  And we drove our regional climate model with global models forced with a very aggressive (and undoubtedly larger than expected) increase in CO2 (RCP 8.5). 

In these model how did the easterly flow near the crest of the Cascades change over time  (we picked a point near Washington's Stampede Pass, but that is close enough)?

The answer is found below.  The figure shows the number of days per year during July through September that the winds exceed a certain speed (6.6 knots) from the east.  The simulations extend from 1970 through 2100 and the black line provides the mean of all the simulations. 

Wow.  The number of strong easterly events....the kind that start fires...DECLINES under global warming.  Let me say that again, it declines.
This makes a lot of physical sense and is consistent with results found by others in California.  As the planet warms, the interior of the continent warms more rapidly that the ocean.   Warms results in less dense air and pressure falls.  Thus, pressure falls more rapidly in the interior than on the coast, which increases westerly flow and decreases easterly flow.  Warming would also lessen the amplitude of the cold highs, like the one that occurred two weeks ago.

So we have observational data that shows that summer easterly flow over the Cascades did not increase during the last 70 years as the planet started to warm.  Furthermore, the gold standard in climate simulations shows late summer easterly flow declining under global warming.    

So the absolutely key driver of major west side of Cascades wildfires--strong easterly winds-- does not appear to be strengthened by global warming.  In fact, the OPPOSITE appears to be the case.  It appears to weaken.

These findings profoundly undermines the hypothesis that the Oregon fires are "climate fires" forced by increasing greenhouse gases.   As a popular TV series might say, this hypothesis is "busted."


But let me take this one step further to completely address the "climate fire" claims. To put the proverbial "final nail" into the "climate fire" coffin.

How Unusual Were the Climate Conditions in the Months Before the Fire?

Were the weather conditions in the months leading the September fires highly unusual?  And has there been a significant observed trend towards considerably worse (dry/hot) conditions as would be expected if climate change was contributing to the Oregon fires?

To answer these question, let's examine the precipitation over crest and western slopes of the northern Oregon Cascades---the region where many of the big fires originated and grew.  Below is a plot of the June to August precipitation over the region from the NOAA/NWS climate divisions data (Division 4 of Oregon) for 1900 to 2020.   The summer 2020 values is not exceptional at all (indicated by small arrow and the horizontal dashed line).  And there is little overall trend in the precipitation for that region.


Clearly,  precipitation in this region does not appear to be changing much with global warming.  Climate models suggests a small decline in summer precipitation (and an increase in overall precipitation) by the end of the century if we continue burning fossil fuels with abandon.

Temperature?  As shown below, the summer 2020 temperature for the western slopes of the Oregon Cascades was neither a record nor even exceptional.  One notes a modest upward trend during the past 30 years of approximately 1F.  That could be the global warming signal.   In any case, such a small warming hardly explains the catastrophic wildfires of this summer.


Finally, let me show you the Palmer Drought Severity Index (produced by NOAA) for September 12th.  The Palmer Index combines temperature and precipitation to evaluate whether drying/drought conditions are present.  This index indicates normal conditions over the western slopes of the north Cascades. 



The bottom line:  this summer was not one of significant drought or very unusual.  Until the September 7-8 fire initiation by the strong winds, the area encompassing fire was below normal in both Oregon and Washington.

Thus, considering observations and modeling, both strongly supporting each other, the major fire/smoke outbreak this month was the result of very, very unusually strong easterly winds, NOT global warming or climate change.

Those pushing the climate change narrative, including some politicians, activist groups and media are simply misinforming the public.


Such deceptive information undermines society's ability to deal with wildfires in an effective way, such as improved forecast management (e.g., thinning, proscribed fires), more aggressive extinguishing of fires before dangerous situations like this month, and better warnings to move people out of harm's way.

Short Comment on Washington Fires and Global Warming

Some individuals and groups have suggested that the explosive fires in Washington State that proceeded the Oregon fires, were the result of climate change.  This is also without any foundation.  Nearly all of the Washington State fires were grass fires (e.g., Cold Springs Fire--190,000 acres, Pearl Hills Fire--224, 000 acres) that were spread by extreme and highly unusual northerly winds.  Grass fires do NOT correlate well with climate, since grasses and small bushes inevitably dry out sufficiently to burn by early summer.  Even if the grass was not initially dry, it would dry out within hours under strong winds.  Such fires are controlled by the availability of ignition sources (often manmade) and strong winds and very powerful (50-70 mph) and unusual winds occurred on September 6th.

Grassland after fire in Eastern Washington this month.
Courtesy WA State Department of Ecology

____________________________________________

Starting September 30th I will be teaching Introduction to Weather (Atmospheric Sciences 101) online.    If you are over 60,  you can audit the class at very little cost through the UW Access Program.  More information on the class is here.

KNKX Surrenders to Cancel Culture.  My blog on this is found here.


79 comments:

  1. Good information. I can already predict how your reasoned evidence will be taken.

    I also predict you will not be invited to the governor's inauguration ball next year.

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    1. Gosh, I don't see why Governor Culp won't want him at the governor's inauguration ball...

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  2. Ah, Cliff Mass, what a robust, excellent blog to wake up to and read this morning! There is much to appreciate in being “schooled” when it is coming from an educated mind.

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  3. Thank you Cliff. I hope this slaps the climate-change-causes-everything Chicken Littles with a little knowledge. It's a small hope, as I'm sure they'll twist and try to refute your data to support their agenda. Got my popcorn ready, should be an interesting day.

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    1. The ones who need to read are the ones who won’t.

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  4. Just because east winds are in the decline doesn't mean the warming is trivial. Higher temps, as you admit means lower humidities. You spent very little explanation on this admitted warming. Also, the downplaying of our future in a warming world seems really short sighted. There are significant changes coming that should have been started to be addressed decades ago, yet we still have arguments with deniers on a daily basis and yet we still have the only major political party in the world right here in the USA that tries to deny this fact.

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    1. The warming by the second half of the century is NOT trivial. Never said that. But declining easterly winds will work AGAINST having major west coast fires...that is the critical point. This blog is not about the warming that will occur this century, it is about the forcing of the fires two weeks ago. And please don't bring in "deniers"...that is a really unpleasant riff on the holocaust and this kind of name calling is not helpful in addressing climate change.

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    2. YOU aren't denying climate change, and I'm not name calling here, I'm stating a fact that we as a country have people (senators) "denying, downplaying, rejecting" climate change at every step and it's a huge problem. Not being prepared for the future is FAR, FAR worse then having media (which exaggerates everything) exaggerate current conditions.

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    3. Michael...we have problems on both sides. Some folks are hyping, exaggerating and distorting the effects of global warming...like the folks claiming the recent fires are the result of it. And we have some folks that are making the error of saying mankind can't effect the climate. What I am trying to do is provide accurate information, based on the best guidance, of the actual expectations of climate change, particularly in our region. Exaggeration of climate change prevents us from getting prepared for the future.... forest management is a good example of that.

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    4. Thanks for having the conversation, your Meteorological knowledge is exceptional and I'm glad you concentrate on the Pacific Northwest.

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    5. Cliff has a great point. When we have (presidential candidates for example) using words like "climate arsonist" to describe people (when the climate change didn't cause the fires) it completely turns off the conversation. And isn't convincing the public more import

      When I hear things like that, it colors the whole thing as a political game.

      It is apparent that there are people who hate that Cliff simply follows the science. So much so that they waited until they could find any little thing to misconstrue and cancel him. Now, when I reference Cliff so many simply dismiss him as a right-wing hack. This could not be further from the truth.

      This conversation gives me hope that an actual discussion can be had. Michael started off with essentially a question that contained loaded words and statements. It was outstanding to see Cliff find the real question and gently instruct.

      It is obvious that Michael is concerned that this sort of blog post will be used excuse human caused climate change, or to deny it altogether. And I am on the other side of that. I see Michael's comment and in my mind I think that is what the media does all the time. Only focus on the drastic and sensational and spread fear in order to manipulate me into doing "the right thing". Truth is the manipulation is what makes all the non-believers (of human caused climate change) into non-believers. The manipulation is obvious, so the assumption is that there is no actual science.

      I am skeptical of human caused climate change. In my short life we have swung from human caused cooling to human caused heating to human caused climate change. My weather man cannot predict the next two days much less the next two years or two hundred years. Cliff has gone a long way in educating me in what his science is and how he forms an opinion about climate change.

      Cliff should be the poster child for those that want to convince the skeptical that human caused climate change is real. Instead, he is cancelled.

      It was refreshing to see the exchange above.

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    6. David H Myhill - Your weatherman cannot predict the weather 2 days out? The science says otherwise, forecasts are VERY accurate at the 2 day period and have increased dramatically over the past decade or two. Also you should learn to understand the difference between "weather" and "climate". Finally, listen Cliff Mass on how he understands that climate change is occuring, because he is correct.

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    7. Cliff, David here is a perfect example of why you need to do a better job of explaining this in context of climate change. You give skeptics and deniers a source of confirmation bias by allowing them to cherry pick the nuances of stochastic events.

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  5. How about posting an equally well-researched and passionately argued column about the very real threats to the future of human civilization as a result of anthropogenic climate change? You're very good at refuting careless attribution of this or that phenomenon to climate change, but your arguments would be less transparently ideologically fueled if your columns regularly drove home the critical urgency of better management of humanity's influence on the planet's atmosphere.

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    1. You mean this one?

      https://cliffmass.blogspot.com/2018/07/the-technology-that-can-provide-society.html?m=1

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  6. I admit I am not an expert in this subject but would like to ask what about that the global warming is not only warming the average temperature of the earth but also is causing extreme conditions from time to time at both extremities (more heat in summer on certain days and more cold in winter on certain days which every almost year or so we hear meteorologists talking about new record temperature, new record precipitation and such)... in regard to this context could extreme cold air be related to global warming. I understand that there could be more factors; but it could be one of them. Please feel free to correct me.

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    1. Not all conditions will get more extreme under global warming. For example, observations have have shown that cold waves have become LESS frequent and weaker in the west under global warming. This is confirmed by high-resolution climate models. Makes total sense, since the Arctic...the source region of the cold air in our cold waves, will become much warmer under global warming.

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    2. If I were you I would reach out to others in his field. It's incredible the difference of opinion that seems to range.

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    3. Sorry for another question. I may have missed and I will search again but if you don't mind me asking if the extent of wildfire has increased over time. Should we also look into that when we talk about wildfires and not just the reasons for a starting point.

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  7. Michael.... I have blogged several times about the expectations of climate change, including greater flooding and loss of snowpack. There are plenty of folks talking about the threats of climate change, including many exaggerating the impacts (like the wildfires). But there are too few scientists dealing with the abject exaggerations and hype. I hope you don't mind that I am trying to provide a fact-based evaluation of climate change claims. Let me know if you find any errors in my analysis.

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    1. @cliffmass what do you make of this article in Nat. Geo?

      https://www.nationalgeographic.com/science/2020/09/climate-change-increases-risk-fires-western-us/#close

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  8. Well said Cliff! Science, facts and reason win again!! Love your fact based analysis on all topics weather.

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  9. Excellent description of the recent events. As an old forester I actually thought we'd get off easy this summer. We had a normal Spring for a change, a few summer showers, unlike the previous several years. However, August and September always burn. The east wind episode changed all that in a day. This is a year similar to the year of the Yacolt Burn, which led to changes in the way forest fires were fought. Those lessons were ignored in the last 30 years of budget cuts to the USFS and state agencies. This years events should change the methods again. You can't continually cut costs, cut crews and encourage building homes in the interface. Air tankers do not put out fires. You still need boots on the ground.

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    1. Including boots on the ground carrying drip torches conducting prescribed burns! As soon as it dries out a little after this series of storms, it'll be time to put a little more smoke in the air. With an emphasis on "little". Though this is more relevant to the dry side of the Cascades, and this blog focused on western Oregon.

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  10. The media and many politicians have also been associating the wildfires in California with climate change. I understand this analysis was not focused on those fires, but based on your knowledge, would you hypothesize there could be a stronger causal relationship between climate change and the intensity/frequency of wildfires in CA?

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  11. such as improved forecast management (e.g., thinning, proscribed fires)
    ...forest management...

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  12. The primary reason why so many in the media and political realm have jumped all over the Global Warming cause for the fires is to evade all responsibility for the calamity. They don't want to address the underlying failures of forest mismanagement, and ever since the controlled burns were virtually eliminated (beginning in the late 70's, if memory serves) retired foresters were sounding the alarm about the devastating build up of dense undergrowth.

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  13. Cliff -- I want to second "Unknown" -- it sounds from your post as if you are studying the CA situation closely, and I'd be curious to hear your thoughts on that. IIRC, the standard line is that record temps and warming have contributed to the fires there via drying in combination with historic poor forest management. Is climate change a fair thing to blame in part for the CA fires?

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  14. Averages only tell so much.

    Have you consider whether the frequency of anomolously strong easterly wind events changes in time? What about the strength of these anomalies--is there a trend there? Do different locations yield similar trends?

    Then there's mathematical questions to consider. How does your choice of averaging impact your plots? What are the standard errors of your averages? Is your ensemble sample size large enough?

    Though the plot seems to support your claim (and it's a reasonable claim to make based on first principles), I wouldn't be so quick yet to nail that coffin until more work is done.

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  15. I think you have argued convincingly that global warming did not have a significant impact on the most recent fires. But I still have some questions about whether in the future global warming will cause an increase in the frequency of catastrophic fires caused by East winds. Why? In both your observational argument and modeling argument you looked at the July-Sept time period, which is reasonable in our current and historical climate. But what about the future? As the winter weather becomes more mild, should we expect the rainy season to be pushed back, such that October would begin to be dry and at risk for fire?

    Currently fires from Easterly wind events are rare in OR because most of the Easterly wind events happen after our wet season has begun and the risk of fire is gone. This is in contrast to CA, where the wet season begins later and these same Easterly winds (Diablo, Santa Ana) in October cause catastrophic fires much more frequently. Even if the severity of these Easterly winds decreases in the future, the frequency of them may actually increase in OR/WA if the length of our OR/WA (dry) fire season lengthens further into the fall and thus more of these Easterly events are able to cause catastrophic fires.

    I am not yet convinced this is the case, but it is something I am questioning, and would love to hear an answer on the subject from someone able to look into whether this should be expected in the next century.

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    1. Very salient point. I've wondered that myself, and say southern Oregon becomes more like mid California ask global climate change pushes the temperatures up. We're definitely seeing it in the 30 years that I've been in this particular location as a gardener. I'm at 2400 feet in the mountains west of the i-5 corridor and we were never able to successfully grow peaches now we've got trees that are literally loaded every year. And I've seen changes in my garden as well things that weren't there when I moved here, and now unfortunately are there such as banana slugs. In my career, I have to maintain the telecommunication site on a mountain that's 5,000 ft. It used to be a lot of xc skiing to get to it in December/January. These recent years I've been able to drive to the top December and sometimes January now.

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  16. I really wish you'd discuss fire and climate impacts within a probabilistic framework. It can be done in a way that is accessible to laypeople.

    This issue is not about climate change *causing* the fires as much as it is about the likelihood they will happen and the likelihood their intensity will increase. This is of course what scientifically-inept media routinely gets wrong when hyping the climate impacts. That being said, I have seen some responsible and well articulated examples of media saying "this is the kind of thing we can expect more of" without attributing its cause to climate. There is a lot of nuance to largely stochastic events. I think you do a good job in some ways of capturing it, but you also routinely fail to articulate the future dangers of a changing climate while putting a lot of effort into debunking worry about those dangers.

    How much confidence do you have that the climate model accurately captures the frequency of wind events? This sounds a lot like predicting the weather under future climate scenarios. There is a lot of work on the impact of humidity and temperature and fuel moisture. For every 1C increase in temp, there needs to be an accompanying 10% increase in precipitation to maintain fuel moisture. I think the number of days with low fuel moisture is predicted to expand significantly under warming scenarios.

    While sure, climate change probably wasnt a major factor in the recent fires, are you suggesting that these type of events will not be more likely with climate change?

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  17. In regard to wildfire, the less logging the better when it comes to the wet Douglas-fir/western hemlock forests of western OR and WA. Unlogged wet forests have high humidities and big trees more resistant to fire. Logged forests have small, densely-planted trees, low canopies that dry out quickly, and a high proportion of small, flammable fuel.

    These wet forests will burn occasionally (250 years or so), precisely under the unusual weather conditions discussed in this post. Thinning or other attempts to "manage" these wet forests will only exacerbate wildfires under these rare conditions. Leave well enough alone.

    Andy Stahl, Executive Director
    Forest Service Employees for Environmental Ethics

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    1. I hope a real forester can reply to this.

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    2. Andy, I didn't see a reference to Forest Management meaning logging - thinning and prescribed burns were specifically noted.

      Can you please comment on that?

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  18. Global Warming made the fires worse, higher summer temperatures dried the vegitation made it drier than it would have been without warming. However, I think that forest mismanagement/allowing forest to become really overgrown is also a big part of the problem. We need to do more prescribed burns and thinning of the forest. A decrease in the frequency of easterly winds would make the fires less sever but more fires in recent years leads me to believe that higher temperatures and overgrown forests are having a bigger effect than less easterly winds.

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  19. Reasonable conclusions, based on factual study!...What a refreshing presentation...made my day! And I will reiterate, as others have done, that your study did not ignore the global warning situation....as you mentioned, a roughly 1% overall warming globally likely is a harbinger of future warming problems....but our recent trouble on the West Coast was the result of a comparative weather anomaly....in other words, "feces occurs"!!! lol

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  20. Why did you include June data on average precipitation and temperature in Oregon? A wet June can contribute to larger fires if followed by a hot, dry august. And that is exactly what happened: August temps in Oregon were far above average, and precipitation was well below average. And late summer in Oregon (and even more so in California) is projected to become increasingly hot and dry as climate change intensifies. Exactly what occurred this year.

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  21. Hmm....above you state: "...the impacts of global warming on the recent Oregon fires were probably quite small." Your conclusion appears to be based solely on single, exceptional meteorological conditions. Other significant contributing factors on the Oregon fires (and probably the recent fires in Washington and California) also include biological factors, such as relative grassland and forest understory fuel load (higher CO2 and longer growing seasons may lead to increased biomass) , grassland and forest understory species composition changes (e.g., more cheatgrass = more intense fires), increased amount of beetle-killed trees, and, perhaps most importantly, historically drier grasslands and forest trees and forest understory plants (due to warmer average temperatures, extreme heat events, coupled with lower precipitation). The preponderance of scientific evidence supports the conclusion that "global warming" tends to promote the biological factors listed above, especially in the American West and Australia, that may contribute to increased intensity and incidents of forest and grassland fires.
    Though I agree with you that politicians and the media often overstate the significance of global warming on extreme weather and fires, I think you also err on the opposite by declaring the global warming has "small" effects on the Oregon fires. Simply put, you didn't consider all the contributing factors to the Oregon fires. The most honest statement would be that you simply don't have enough data to make conclusions with high confidence one way or the other.

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    1. I provided my logic in the blog. The key driver of the fires...the strong easterly winds... have no apparent connection with global warming. That is very important don't you think? And there is no trend to more extreme dryness in the region...

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    2. Please provide evidence of your claims about dryness. I have heard the opposite. Fuel moisture is a very important consideration.

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    3. The Cramer paper you cited mentions 2 drivers of large fires in the Northwest: small fires and sever east winds. Both are necessary for large fires, and though the evidence you have provided does suggest that climate change will not make strong easterly winds more frequent, the situation with regards to small fires is not as clear (at least with the provided data). The biological factors mentioned by RG Stout could potentially increase in the frequency of small fires. Without quantifying the relative impact of global warming on both drivers it is not possible to confidently predict future fire frequency.

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  22. Might climate change be causing an increase in insect infestations of Pacific Northwest timber stands, which in turn makes forests more susceptible to fire in general? Then when appropriate climate conditions/human-caused fires occur, fires that otherwise would be termed "normal", instead become these mega-fire disasters.

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    1. I have found no evidence of insect infestations on the western side of the Oregon Cascades.... do you have reference for that? That is an east-side problem.

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    2. I can only reply anecdotally and from a layperson's standpoint, but there's no question that out here in the San Juan Islands we're losing trees at a rapid rate to bark beetles, only over the last couple of years.

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  23. Thanks for this post.
    It's great to hear your models, but your final analysis seems very much tied up in theory. As in your Models point to these fires not being climate related, which is completely fair. But they ignore that the individuals who live in Oregon (like my Family) for decades, and farm there and are very very connected to the land and the very granular details from the soil to the trees, the vast majority of that community confirms that these last 4 seasons have had moments of the core land and fauna drier than any time in the last 4 decades. That's not a statement of quantities of rain, but of moments where they have had to react to extremely warm and dry conditions to maintain their livelihood.

    Yes, winds to your point cause most of these fires, and you show great evidence on why the WIND isn't a part of Climate change concerns (thank you for that). But it seems to ignore that the combination of the Wind and unprecedented conditions have COMBINED to make these fires absolutely hell. Spreading faster and covering more land than in any recent history.

    To put it a different way, you seem to be speaking - accurately I might add - to only a PART OF THE STORY, yet your conclusions seem to make it come off as the complete story.

    Scientist to scientist, that can be very misleading to your audience. I believe you to be better than that.

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    1. Don't understand your point. I examined BOTH the winds and antecedent conditions. The winds were extraordinarily unusual but the antecedent conditions were not. I showed all the information---how is that misleading the audience. I have provided my chain of logic.

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  24. Cliff, does this analysis extend to the fires in California? I appreciate the evaluation of our local situation, but the national discussion on the effects of global warming also includes California. Without an evaluation of the California situation, we're left with an incomplete view of the situation.

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    1. I was only talking about the NW situation. Every region is different.

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    2. I'd be curious to hear your interpretation of the California situation.

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  25. This is why I listen to you Cliff!! Thankyou for all the work you do to give us the truth!

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  26. I appreciate your post and must say that I am not a meteorologist. That you have authored many papers and written books is immaterial in my understanding of what the methodology of science would say about how to evaluate your statements. Reference to authority should not be the standard but rather the data.

    With regards to the recent fire events, you mentioned the high winds from the east but didn’t go further to examine what was behind those winds. It is my understanding that the cause of these winds was a post tropical cyclone in the eastern Pacific. To what extent are such events consistent with the movement of heat from the tropics to the northern latitudes as a result of planetary warming? Does your model account for this?

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    1. Knowledge is important, particularly knowledge of the particular issue under consideration. Are you suggesting that is NOT the case? Read my blog... I talked about why the winds occurred. And that they should decrease under GW. Please read the blog carefully.

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  27. I couldn’t help but notice how often in your post you mentioned that conditions were “very unusual” or “unprecedented.” Isn’t that the very definition of climate change? A changing climate would produce more unprecedented and unusual events, wouldn’t it?

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    1. Paul... an interesting point. No...one can get extremes even without a changing climate. Records can and do occur even without a long-term evolution of climate....conditions just come together to create them. Now some extremes are expected to increase under global warming, for example temperature extremes and extreme precipitation. But even if the climate did not change, extreme records would occasionally be broken...cliff

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    2. Extremes are infrequent deviations from the mean. The magnitude of future extremes are projected to increase with climate change (= more unprecedented and unusual events, like Paul says), and the frequency of events which are currently classified as extreme (unprecedented/unusual) are projected to increase as well.

      What are your assumptions? You are putting a lot of faith in modeled future high-wind frequencies. You seem to be ignoring the projected increase in fire season length and very low fuel moisture days. If the fire season is a month longer, or the number of days where fuel moisture is perfect for wildfire, you have to factor that into the probability that a wind event occurs simultaneously with ideal fire conditions... Maybe the probability of a wind event is 25% lower, but the number of days where conditions are ideal is 50% higher. You're making assumptions and missing nuance.

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  28. Cliff
    Great overall
    Also contributing factors are 1. Power lines that are broken during windstorms. Malden is one of many. You pointed this out several years ago in several CA fires. And we have no solution except very expensive underground lines
    2. In WA we have many grass fires due to us introducing cheat grass, annual Japanese grass etc. sometimes those fires get into timber as well. Hanford burns often due to zero barriers and lots of non native annual grasses.

    There are many factors

    Thank you

    Rich

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  29. Worldwide fire monitoring by NASA, unfortunately last updated in 2017 (gee, wonder why) https://www.nasa.gov/image-feature/nasa-sees-intense-fires-around-the-world

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  30. Maybe all those arsonists they caught had something to do with it too...

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  31. Once again our governor is lying to the world

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    1. I would not put it that far, but he is mistaken about this. Folks make mistakes.

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    2. No in fact he isn't. You're making the same fundamental mistake you make over and over: making long term assertions of fact based on a singular event. The fact of the longer season and drier fuel load made this more severe. This is a fact.

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  32. According to komo, for Seattle this was the 7th warmest summer since 1945, and the 18th driest. Granted Seattle isn't the same as the west slope of the Oregon/Washington Cascades, but this does seem to conflict with Cliff's statement that this summer was "not exceptional at all".

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    1. Lefty... I provided the data for the area in question...which is NOT SEATTLE. The Palmer Drought index for the AREA IN QUESTION was not unusual

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  33. Nice piece, Cliff. A few typos, garbles, in this paragraph:
    This makes a lot of physical sense and is consistent with results found by others in California. As the planet warms, the interior of the continent warms more rapidly that the ocean. Warms results in less dense air and pressure falls. Thus, pressure falls more rapidly in the interior than on the coast, which increases westerly flow and decreases easterly flow. Warming would also lessen the amplitude of the cold highs, like the one that occurred two weeks ago.

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  34. A reasoned and objective perspective on the ongoing MSM freak out about the fires:
    https://fee.org/articles/forest-fires-aren-t-at-historic-highs-in-the-united-states-not-even-close/

    Records do not support the screaming regarding these events as somehow apocalyptic or even highly unusual. In fact, the years of 1930 and others of that era were of a magnitude many times worse.

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  35. Following on the previous comment...I has a chance earlier today to chat for a few minutes with a wildland firefighter. I asked him whether there was a predominant reason for the various fire starts in eastern WA, and to what extent arson played a role.

    He replied that a full analysis of all the fire starts in WA is ongoing and will take time to complete. And a number of the fires, especially those down towards Yakima, are either confirmed or likely to be arson.

    Then he added something that was news to me, although perhaps it's not for those who followed the fires closely. The folks who investigate fire starts in WA, he said, are already very confident that arcing power transmission lines, caused in turn by high winds, played (his words) "the biggest role" in causing the fires in eastern WA. In other words, a repeat of what happened in the recent, very deadly, Napa/Sonoma fires down in the Bay Area.

    Just wanted to pass that along, since it came from a credible source, and I know the issue of what to do about arcing high-voltage lines during wind events has been a VERY contentious issue in California. (It doesn't help that PGE, the biggest utility company in Northern California, ranks somewhere between Hepatitis C and child molesters on the public popularity scale.)

    Cliff, I believe you even did some blog posts on the topic of using wind prediction models to shut down at-risk transmission lines before they can cause fires. Any thoughts about whether the public utilities here received timely information about wind events and/or had an opportunity to shut down transmission lines at risk of starting fires?

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  36. Great post. Here's to realism and realities. Ain't science great? I much prefer it to B.S.

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  37. Hi Cliff-
    I posted a comment earlier but apparently it did not go through.

    Yes, we may a lower number of days with east winds, but rather wondering about the severity when they do occur. What do you say to the "lazy jet stream" or deep dips in the jet stream theory (as a result of climate change) and the resulting larger pressure gradients that they bring super strong east winds?

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  38. Great blog post Cliff. Very similar analyses pertain to California fires. The political push to blame climate change only endangers people by promoting the wrong remedy and obscuring the best practices needed to minimize damage from wildfie.

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  39. The same nuts that mainly push the global warming, climate change, or whichever term they're giving it this week are the people that think you can pick your gender, that there are 4367306 genders, that rioting and looting is a "peaceful protest", that 2+2=4 is racist and not true, and that math, written language, reading, history, and pretty much everything else is racist. I could list dozens of more examples of their insanity.

    They also think a guy clearly suffering from dementia who now thinks the entire population of the country has died whether from gun wounds or the kung flu should be president and they want to impeach the current president for doing his constitutional duty (aka, HIS JOB) of nominating a new SCOTUS justice.

    The point is that these people are all mentally ill and nobody should put any value in what they say. The fires were started by arsonists or if not all by arsonists, some by accident.

    It also doesn't help that they keep crying wolf with the big bad global warming/climate change and their predictions continually don't come true. First off, NYC was supposed to be frozen as they said back in the 70s when they were predicting a mini ice age. Then it was supposed to be under water by now along with places like Miami and other coastal cities yet look at that, never happened. The climate change cult can't get anything correct yet some people keep listening to them. It's mind boggling.

    Then you have the fact they blame every single weather/climate event on their climate change belief. If it rains it is climate change. Doesn't rain it is climate change. Hot it is climate change. Cold it is climate change. Snows it is climate change. Doesn't snow it is climate change. Hurricanes it is climate change. No hurricanes it is climate change.

    So absurd and it is embarrassing that people still buy into this glorified death cult.

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  40. Cliff, my father's family fought the Tillamook fires as did he the last of the fires in 1951, he was busy in the Pacific during the 45 fire.

    Most people have no idea about the "Tillamook Burn", obviously global warming had no impact on these fires, but no one was building homes in the interface back then.

    My dad's uncle was the head forest ranger and we would visit and stay there, I recall driving around and visiting the watch towers with him (60s).
    Fires are not unusual events, the winds out of the east in late Aug early Sept are what causes these fires to spread so fast. Not Climate change.

    Folks should check out Tillamook Burn on youtube, ( 4 large fire, 1933-51).

    Thanks Cliff

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  41. Yes, climate change is not an explanation for every weather event unless you're a news editor and need eyes. I remember Ron Sims declaring a climate change emergency due to a winter drought, then on cue we had record spring rains that filled the reservoirs.

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  42. All Cliff is saying is don’t blame the “natural” weather events for climate change this time. Humans continue to dominate in how we are destroying our environment. Laps ahead but weather is catching up. That uncertainty in the face of these last events are truly frightening. I wish people could see that.

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  43. Outstanding blog with facts to back it up.
    Please do a blog on forest management to curb these rampant fires..
    Laurie long island

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  44. Hi Cliff, thanks for the blog post. I was wondering if at some point you would consider doing a post about how climate change may affect the climate in Seattle / the pacific northwest. Thanks!

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  45. Cliff, I have to disagree with your implication that this years fire season weatherwise, at least here in Central Washington, was not too severe. We had a very dry spring and summer with a near record stretch of rainless days at Wenatchee beginning in mid-June and just ending today (Sept. 23). Temperatures have been above normal through the summer and we observed some very low humidity days. The only thing that saved us from having a fire situation probably similar to Oregon and California, besides people being careful with fire, was the almost complete absence of lightning storms.
    Also, you seem to imply that "forest mismanagment" may be the main factor in recent years spate of large fires in Eastern Washington. Many of these large acre fires, including this years, burned much of their acreage in borderline forest/grassland areas or in the mainly shrub-steppe terrain, where "forest mismanagement" is little or no factor. I suggest that the recent weather pattern favoring wet springs, which encourage heavier growth of grass/shrubs, followed by dry, warm summers may be more of a factor. Looking at
    the Washington State climatologists web page showing PNW Temperature, Precipitation and SWE Trend Analysis appears to show this trend during the past 20-25 years toward wetter springs and drier, warmer summers at stations such as Ellensburg, Wenatchee and Winthrop.

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  46. Thank you so much, Cliff, for this analysis that provides actual context. You and Daniel Swain are my favorite weather bloggers. I am concerned about climate change and disgusted that the federal gov't ignores it, but I cannot stand the way most media practice advocacy-based science rather than science-based advocacy on any climate-related story, selectively grabbing the most alarmist images, quotes and soundbites that don't tell the whole story. When do they ever present data to detail the full context of extreme weather events? I guess it's not in their best interests... Kudos to you for calling them out

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