Wednesday, May 20, 2015

Drought Misinformation

There have been a number of stories in the press and on the web about water issues this summer in the Northwest; some are reasonable but a disturbing number are exaggerating and distorting the situation, predicting a catastrophic wildfire season and billions of dollars in crop loses.  And some folks in the political arena are playing a bit lose with the facts as well.

You want some examples?  Crosscut calls out a SUPERDROUGHT.

This over-the-top piece does not stop with this year:

"The 2015 superdrought will likely be a harrowing experience for many state citizens, and could be followed by another, similarly terrible year.'

 Others talk about a TINDERBOMB due to low snowpack

Or in the Oregonian:

Will there be a superdrought this summer over the Pacific Northwest?   Will low snowpack bring huge wildfires?  Let's get beyond the hype and look at data and forecasts.

First, let's be clear.  There is no drought over the Pacific Northwest and by that I mean no precipitation drought.  For the last six months, here is the % of normal precipitation over the western U.S.  Most of Washington State and the eastern half of Oregon received 90-110% of normal.  The rest was at least 70%.   California and Nevada is a different story, with real drought.   You can see why William Shatner wants our water.

What about conditions on the ground?  One of the most considered measures of drought is the Palmer Drought Severity Index.   Here are the latest values.  Most of Washington State is near normal and eastern Oregon is wetter than normal!

What about the the NOAA crop moisture index?  Normal.
And the last two weeks have been unusually wet  (green and blue) over the eastern side of the Cascades.

And this evening's WRF precipitation forecast for the next 72h looks like something that would inspire Noah to start building his ark:

While the latest forecast of total rain over the next 9 days from the National Weather Service's GFS model would bring happiness to any Northwest duck.

And keep in mind that Columbia River flows, draining off the higher terrain of British Columbia, which had a better snowpack AND more precipitation, will only be slightly below normal.   Plenty of water for hydropower, irrigation from the Columbia, and fish in the river.  And because of substantial reservoirs and wise stewardship, nearly all of the populated areas of the region will have sufficient water.

So this talk about the Northwest being in a drought, super or not, is really problematic.    We have had near normal precipitation, our soil moisture is near normal, our reservoirs are full, the Columbia is near normal, and the drier parts of the state are being hit by wetter than normal conditions during late spring.    

We DO have a lack of snowpack because of the warm temperatures last winter that resulted in rain but little snow in the mountains.    So maybe it is ok to talk of a snow drought, but that is a bit confusing to some perhaps.  This snow drought will be problematic for fish on some rivers (e.g., draining the Olympics), but there is little we can do for them.  Nature is cruel sometime.

So how worried should we be about wild fires due to the low snowpack?   And what about other factors?

I have talked to my colleagues in the wildfire business and most of them feel the snowpack issue is overblown.   They tell me that the key determiner of whether there will be extensive fires in the summer are:
  1. Whether we are much warmer than normal in July and August
  2. Whether there are a lot of thunderstorms to initiate fires.
  3. Whether we are much drier than normal in July and August

Regarding the last bullet, we are normally dry during our summer, but rain can moisten the "fuels" and lessen the fire risk.

There is good reason to suspect snowpack has only a small impact on wildfire frequency and intensity.  First, the differences in snowpack between good and bad years is pretty minimal by the time of the main fire season, which is roughly from mid-summer to early fall.   Second, differences in snowpack early in the season between good and bad years is mainly at higher elevations, while most of the significant fires, and certainly the ones the affect most people, are at low elevations.   To show this, here are the areas of the major fires of the past 15 years.  Most are on the lower slopes of terrain east of the Cascade crest or in relatively low (and snowfree) coastal mountains.

There are a few papers correlating lack of snowpack with increased wildfire threat (e.g., Westerling et al. 2006), but I believe they have a fatal flaw.   Their low snowpack years were also precipitation drought years, which is NOT TRUE of this year.

So if snowpack won't be a major issue, what about temperature, precipitation, and thunderstorms?

Our best guidance for the seasonal predictions is the NOAA Climate Forecast System (CFS) model.   For temperature, its forecasts have been clear and robust.   Warmer than normal (see below) over our region.   That would enhance wildfire risk.
 Precipitation is a different story.  Nearly normal over Washington, but a bit wetter over eastern Oregon.
Predicted soil moisture?  Generally, near normal except for eastern Oregon, where it would be wetter than normal.
But then there is the thunderstorm issue...and folks, THAT is the wildcard.  The enhanced precipitation over the Rockies suggests more thunderstorms over that region and perhaps into eastern Oregon.  Might those thunderstorms get to up and start fires?   On the other hand, the CFS model predicts enhanced ridging over our region, which would lessen thunderstorms.

The bottom line in all this, is that a more nuanced view of the current "snow drought" situation is called for and the prediction of more wildfires is no slam dunk.  Talk of superdroughts is really nonsense.  

There is certainly no reason to expect fewer than normal wildfires and the warm temperatures will modest increase wildfires potential.  But the lack of snowpack is a minor issue.   Much is riding on the frequency of thunderstorms, and there is considerable uncertainty how that will play out.

As I have said many times, this year has many of the characteristics of 2070, when global warming will be significant.  That is why the work of Governor Inslee and the Department of Ecology to take all possible steps to adapt to a low-snowpack year is appropriate and welcome.  We need to figure out how to deal with a lack of snowpack, while preserving our agriculture, drinking water, and as much as possible of natural fauna/flora (e.g., salmon).  But hyping and exaggerating the situation is not helpful.

And for those in western prepared for thunderstorms later tomorrow and into the early morning hours of Friday.


Buddy said...

Cliff that is great analysis. I left a comment a couple weeks ago. I'm young and local, only fighting wildfire last couple years for a summer gig. Fire season is explosive every year on the lower reaches of of the Mts. And the area that covers the upper areas of the crest give or take a couple weeks due to snowpack. Yes this years melt out is faster than normal.

Yet it's about a trigger. Number one, lightning. Second, human activity and responsibility. Finally condition of the fuels.

I still believe it will be an above average season for the PNW. How incredibly warm and relatively dry it's been since March. Don't let last weeks moisture fool you.

Local fire officials say El NiƱo summers bring wet conditions to the interior NW. To me that's bad news. Most of that will be the form of convection which even on the wettest of summers cant snuff out major fires. I love the stable cool marine influence (which can cause high wind) on forecasting fire behavior. We are ready for the 2015 season.

Placeholder said...

Oh come on. It's so much more fun to scare people and predict the end of the world, especially when all of it is accompanied by the usual righteous declaration that it's all the fault of The Oil Companies, the Koch Brothers, or simply Those Republicans.

Michael Snyder said...

Im usually in high agreement with you Cliff but the US drought monitor disagrees.

Mountain areas under moderate drought, western WA abnormally dry and some parts of eastern WA under severe drought.

DSP said...

Yet this "U.S. Drought Monitor" map shows parts of Washington to be in "moderate" to "severe" drought and all of SE Oregon to be in "severe drought" to "extreme drought".

Sysiphus said...

In terms of long-term solutions to the predicted lower snow packs, what about groundwater storage? Presumably we have an aquifer in E Washington that would provide adequate storage to tide us over during the dry months.

A few well-placed pumping systems to move water around and over mountains as necessary) and buried pipelines (to avoid the massive wastage that they get in California from aqueduct water loss) would do the trick. This would even permit DFW to maintain historic river flows through the summer to protect salmon. Without a snowpack, those rivers might dry out in the late summer, which would be devastating to the the early fall salmon spawning season.

Cliff Mass said...

DSP and Michael Snyder mentioned the Drought Monitor graphic. It is really not very useful. It is completely subjective....and put together by individuals in a highly subjective way. Objective measures show no drought in soil moisture or any other measurable parameters. Please look at the documentation of the Drought Monitor graphic on their web site..cliff

Placeholder said...

The drought monitor is full of it as it concerns Eastern Oregon. My friends and family there tell me it's been raining there for a few weeks. The drought monitor hasn't changed. Also, the article that Cliff mention vastly overstated the situation in California, and falsely alleged severe drought in the Midwest. The article is pushing a radical pseudo-"environmentalist" line. Crosscut's "environmental" coverage cannpot be trusted.

John Franklin said...

Cliff - which of these indicators used by the Drought Monitor do you consider subjective?

1. 1-3 and 6-60 month precipitation.

2. USDA/NASS Topsoil Moisture

3. Keetch-Byram Drought Index

4. NOAA/NESDIS Vegetation Health Indices.

5. snow water content, river basin precipitation

6. Surface Water Supply Index

or their "other indicators (groundwater levels, reservoir storage, and pasture/range conditions).

Cliff Mass said...

John Franklin,
The point is that the drought monitor is an absolutely subjective combination of all kinds of indices and measures, some objective, some not. This is not science, nor useful. ..cliff

mosierfire said...

Fire behavior above snow line will also be a wild card this year.

The Two Bulls Fire last June showed that 1,000-hour fuels were parched after a dry (precipitation) fall and winter, with more snow than this year. 2015 is the third year in a row with similar conditions going into summer, and sshaping up to be the third year in a row of "Junuary" cool, wet late spring accompanied with, and followed by weeks of lightning storms, today being a fine example down here in Wasco County.

-- Jim Appleton
Fire Chief
Mosier Fire District

Placeholder said...

Seattle's "progressives" don't care for any facts that might conflict with their religion, as Cliff has found out on a number of occasions.

Dalton said...

"Wildfire season in Oregon expected to start earlier, last longer, experts predict"

Boy that sure is some alarmist hyperbole right there. I read this and just about grabbed my bug out kit to get the hell out of dodge. Turns out it was just the Oregonian trying to rile everybody with a perfectly reasonable statement that still strikes me as fitting with the facts.

Trees in lower elevations leafed out a lot sooner than usual. The cheat grass was brown in the hills by late April. The tinder is there already. Fire season, the season during which the conditions for fire are favorable (not the season during which fires are actually burning, thus the ignition point is moot) has already started. Since it started earlier than usual, assuming it ends at the same time, it will also last longer than usual.

I'm with you on "Tinderbomb" and some of the other statements, but I think you needlessly picked on the Oregonian to simply drum up your own rhetorical click-bait about how the media gets it all wrong.

jeb Thurow said...

Thanks Cliff,
The local news reported that the newest drought monitor had Westen Wa in drought. I was under the impression that "normal" or "Average" meant that 50% of the time we would have more rain than this and 50% of the time less rain than this. At less than 1" below normal are we not within a "normal spring"I do agree that the Governor and the dept of ecology need to keep close tabs on this but I get worried when politicians start quoting numbers,because someone's going to get taxed to fix it

sunsnow12 said...

Cliff -

Thank you for being one of the very few in the scientific community willing to stick their neck out on this subject and call this for what it is. Also, kudos to SPU for honestly discussing the situation as well. The misinformation (and that is a nice way of saying it) needs to stop and the public needs to be talking about it. Kudos to you for being willing to lead this.

Michael Snyder said...

If the US Drought monitor is "not useful" then what do you suggest we go by as far as drought information?

sldulin said...

Excellent use of your clear writing style and good graphics to present a persuasive argument. I'm persuaded. I claim no expertise beyond 60 years local observation, but I think you are right to de-couple snowpack totals from wildfire severity. In my experience Northwest wildfires are each one unique events whose ultimate and proximate causes seem clear in retrospect but not necessarily evident at the time. Such factors as heavy fuel loads and low precipitation and wind events exist very often in isolation but you really need to get a combination at the right time to get a situation like last year's Carlton Complex. I do worry that we get too fixated on wildfire as the signature effect of drought on our region. We currently have a lot of very stressed forests with a lot of sick trees, I can't imagine an El Nino summer will be beneficial.

smokejumper said...

Whoa Cliff. An awesome storm occurred over the city of Yakima this evening. I'm 30 years old and can say this was in the top 3 I've ever experienced here. There was a prolific amount of lightning in the cell. Wondering if you can see a strike count.

Placeholder said...

Here is where you go for useful drought information. NOAA has been fiddling with some historical data, but they haven't (yet) gotten around to fabricating this stuff.

lostarrow said...

While I have seen the historically low snowpack numbers that have published recently, I was wondering if there was data available for snowpack readings at higher elevations in the Cascades which seem to me somewhat are closer to average.

lostarrow said...

While I have seen the dire snowpack numbers that been published recently, I was wondering if there was any data available for readings at higher elevations in the Cascades which seem to me are closer to average.

mosierfire said...

Re: Smokejumper
Wild Fire Management Information (WFMI) puts it at 144 positive strikes and 146 negative strikes over an area from White Pass to Toppenish, with the bulk of activity from Selah and Ahtanum down into White Swan.

beerfish said...

As a former wildland firefighter you left out one important aspect:

Wet weather in the late spring leads to increased growth of fine fuels (grasses) that then are extremely flammable once that dry July and August hit.

Michael Snyder said...

So much for "useful" drought information.

The Palmer index has limitations that are especially unreliable when used for WA state.

The Palmer index: Palmer values may lag emerging droughts by several months; less well suited for mountainous land or areas of frequent climatic extremes; complex—has an unspecified, built-in time scale that can be misleading.

Its also known for its weaknesses with snow-cover and frozen ground.

The Palmer Drought Severity Index: Limitations and Assumptions, Journal of Climate and Applied Meteorology, Vol. 23, pp. 1100–09, July 1984

Tom Merriam said...

"And keep in mind that Columbia River flows, draining off the higher terrain of British Columbia, which had a better snowpack AND more precipitation, will only be slightly below normal."

But the rest of the drainage basin snowpack is well below normal and is larger area. Not sure about your statement that the flow will only be slightly below normal. According to NOAA's 120 day forcast the flow is predicted to be 65% of normal, that seems significant to me,
Of course this could all be moot if we receive significant summer precipitation.

Ansel said...

Hi Cliff, I thought you promised me a thunderstorm. You specifically mentioned Western Washington. I am on the Bothell-Mill Creek line- which is in the convergence zone! What happened to it? I didn't even get any rain...

Cliff Mass said...

Michael Snyder,
You are not following my point....the Palmer Drought Index is valuable where there is no snow...which is MOST of the state. ...cliff

Katie said...

This is not very related to the drought (since it's pouring right now), but I was wondering why for the past two weeks all our moisture seems to come from the east? (I live in Pasco.)

Meerkat said...

I was in e wash in early May to plant a garden and it was bone dry-- a foot deep dry soil, grass was dessicated at a time it's usually as green as old ireland. Spooky year over east if you ask me. Hopefully better now.

Apricot trees bloomed so early there were no pollinators; now, maybe 5 apricots this year. The bloom was weeks early.