The Northwest Wildfire Season Was Dominated by Grass and Range Fires. That Has Implications.

With the recent rain and cooling, the wildfire season is essentially over for the Pacific Northwest.  

In terms of acreage, 2026 has been one of the most prolific wildfire years of the past decades. 

Considering the past 50 years,  it was the leading wildfire year in Oregon and number two or three in Washington State.  Most of the major fires were started by a limited number of lightning "storms".

But now, the key point.   

The great majority of the wildfire acreage occurred in grass and range vegetation, not forests.

Importantly, grass and range fires have little to do with global warming and climate change.

To demonstrate all of this, let's begin by examining the areas burned  this year, using graphics from the U.S. Forest Service (below, pink shading shows the fire area this year )

Massive fire area in Oregon.  Nearly all in the grassy/range areas of the eastern side of the state.  

In contrast, essentially no fires over western Oregon, west of the Cascade crest.  One of the lowest wildfire years on record for the western side of the state.

Like Oregon, western Washington has also escaped wildfires this year (see below), and for the same reason:  a lack of strong easterly wind events.  Most of the wildfire area in Washington State has been in grass and range vegetation, but some of the fires have extended into trees on the slopes of local terrain (e.g., the Little Giant Fire)

What about the origins of the fires in the two states?   

According to the U.S. Forest Service, the vast majority of fires were ignited by humans (e.g., arson, power lines, debris burning).  The major acreage fires were nearly all started by lightning.

By simple inspection of the graphics, it is clear that grass/range vegetation, not trees, has dominated the 2026 fires in the Pacific Northwest.   

Asking various AI systems to compare the satellite-based fire areas to satellite-based land use provides similar answers. In Oregon, the dominance of light vegetation is overwhelming (see below), with three-quarters of the fires in grass and brush.  For Washington State, they estimate about 60% coverage by light vegetation.

Examining the fires manually, looking at BOTH satellite assets and surface imagery, it is apparent that the satellite approach underplays the availability and importance of light vegetation.  To illustrate, below is an image from a "forest" area within the very large Sinlahekin fire of north-central Washington.

 

There may be some trees, but grasses and low shrubs dominate. I have looked at dozens of other areas in both states, with similar results.  

Based on my review, I would suggest that at least 80% of the Oregon wildfire area this summer was in light vegetation and at least 70%  of the fire area in Washington.

Thus, this year was mainly a problem of flammable light fuels that dry quickly (hours to days) and are always dry enough to burn by July in our region.

Modest global warming over time was not a factor in the flammable conditions at the start of summer.

Furthermore,  our region has been invaded by non-native, highly flammable grasses and light shrubs.  These are human-forced vegetation changes that greatly enhance fire potential.

And with decades of fire suppression, our forests have become unusually dense and full of debris, and thus highly vulnerable to wildfires

In addition, the region has extperience downward trend in lightning.  So global warming is not forcing more lightning ignitions.

The bottom line is that human-forced global warming had very, very little to do with the major Northwest fires this summer, and those claiming a connection are providing problematic information to the public.

A "Perfect" Storm Hits the Northwest

If you were to order a "storm" for the Northwest, you would request one that drops lots of rain over the crest and eastern side of the Cascades, decisively ending the wildfire season and providing needed moisture to late-season crops.

To do so would require an upper-level low centered along the northern Oregon or southern Washington coast, which would swing moisture in from south into eastern Oregon and Washington.  

Exactly what is happening this weekend (see upper-level map for 2 PM Saturday).

Upper-level chart (500 hPa pressure level) for 2 PM Saturday. 

The resulting clouds swirling around the low are impressive:

As was the radar image last night.

Consider the  "storm" precipitation totals as of this morning around 6 AM (below).

Nearly an inch at some locations east of the Cascade crest as moist air swung around the low and rose on the eastern slope.

Looking forward, the total precipitation predicted through 5 AM Monday (by the UW WRF model) is quite impressive, with several inches forecast east of the Cascades, exactly where we need it to end the fire season

And believe it or not, it is cold enough aloft to result in some snow at higher elevations (see below)

We will have a warm/dry period this week, followed by the return to much heavier precipitation in ten days.  Welcome to autumn.

The Effects of "Super" El Ninos Are Surprisingly Different Than Some Suggest

It is now clear that a very strong or "super" El Niño will be in place this year.  

Some are even calling it a GODZILLA El Niño.

Several media outlets and amateur YouTube channels/social media sites suggest the impacts will be like a regular El Niño on steroids: very warm, wet, with a low snowpack.

For example, Oregon Public Radio:

The Bellington Herald throws caution to the wind, predicting drought and floods!  Plus fires. Devastating impacts for Whatcom County.  Meteorological "end times".

But there is pushback on these apocalyptic predictions.  

For example, the Summit at Snoqualmie folks looked at the snow statistics associated with very strong El Niño years and found snow totals near normal (link here)

And in my previous blog on very strong El Niños, I found the same thing: Northwest snowpack can be quite decent during "super" El Niño years.

So how can this be?   

Why do moderate El Niños cause one impact and "super" El Niños result in something different?   

Let's figure this out using real data.

The figure below shows precipitation associated with moderate, strong, and very strong ("super" or Godzilla) El Niño years for October through March.

The difference from normal is shown, with blue and purple indicating above-normal, and yellow and red indicating below-normal precipitation.  

Moderate and strong El Niño years are drier than normal over the Northwest, but "super" years, like this year, are WETTER than normal.

No drought expected.  Plenty of water for our region.

Surface air temperature?

Moderate and strong years are close to normal over the Northwest (below).  For "super" years like this one, temperatures are very modestly warmer (about 0.5 C or about 1F; see the blowup below). 

No wonder snowpacks remain decent for Super El Niño years:   only slightly warmer but with much more precipitation.

The Snoqualmie Pass folks were on to something!

Finally, can we explain these differences in a more fundamental way?  

To do so, below are upper-level weather charts (500 hPa heights; think of these as pressure around 18,000 ft)

All El Niño events are associated with an enhanced low-pressure system over the northeast Pacific (the purple colors).  Air circulates counterclockwise around lows.

For the moderate El Niños, the low is centered well offshore. Strong events have the low much closer to the coast, which is not favorable for precipitation over our region.  But for the "super" events, the low is more offshore, producing more moist southerly flow over our region.

Just right.

In summary, past events suggest that the Northwest impacts of a very strong El Niño are quite different from its moderate relatives.  

Importantly, Northwest drought conditions are not expected with a very strong El Niño, and there is good reason to hope for a near-normal snowpack.

Media and social media predictions of some kind of meteorological "end of times" are without support.

More Good News Regarding Northwest Wildfires

The wildfire season in the Pacific Northwest is rapidly approaching the endgame, with huge declines during the past month.

To illustrate the profound change, consider the satellite-based wildfire observations for today versus one month ago (below).

Today,  there are only a handful of hot spots on the northeast side of the Cascades.  No apparent fires in Oregon.

A month ago, it was a different story with numerous and massive fires (mainly the result of lightning) in both states.

Air quality is good through most of the region today, with some very localized degradation near some of the smoldering fires.

A sharp drought of low pressure will move through over the weekend, mainly to the south of Washington.  

As a result, southern Washington State and Oregon will see substantial precipitation (see totals through Monday morning below).   Bad for fires.

And temperatures should be cooler than normal from Friday to next Wednesday (see below), which should help suppress fires as well.

Pretty confident that this is the endgame for Washington/Oregon fires this year.

In a future blog, I will make the case that 2026 was predominantly a grass/range wildfire year in the Northwest.  The quote on AI source:

In Oregon—which surpassed historical records with over 2.3 million acres burned—short grass and dry brush served as the primary fuel source for roughly 1.8 million of those acres

And something else.  This is turning into a very attenuated wildfire year for California, with this year possessing less than half of the average over the past five years (see below).  That could change, of course.

Seattle and Weather Disasters. We Can Do Better Than Los Angeles and New Orleans!

Weather prediction has become far more skillful in recent decades, with nearly all major regional weather/climate threats accurately predicted days in advance.  

Unfortunately, several major cities have not taken advantage of the profoundly more skillful forecasts, resulting in unnecessarily severe loss of life and property.

For example, Los Angeles experienced immense damage and many deaths from the 2025 wildfires, the result of a well-forecast Santa Ana wind event.

Los Angeles, January 2025

Thousands died in New Orleans from Hurricane Katrina, whose track was skillfully forecast several days before.

Seattle was caught unprepared for a well-predicted snowstorm in 2008, leading to a crippled city and the mayor being kicked out of office.  In 2022, the region was not prepared for a well-forecast freezing rainstorm.

I just published a paper on the topic: Excellent Forecasts but Poor Outcomes: Why Can’t We Do Better?

Seattle and the vicinity are vulnerable to well-forecast environmental threats, such as:

• Windstorms associated with Pacific cyclones
• Downslope windstorms descending the Cascades
• Snowstorms
• Ice storms 
• Wildfire smoke
• Coldwaves 
• Heatwaves
• Heavy rain and flooding

To deal with all these threats, Seattle should create an ENVIRONMENTAL WARNING SYSTEM.  

A system that would monitor the potential for such threats, provide online forecasts of their impacts, and push critical, site-specific information out to smartphones and other devices.

Here is a sample of what I am thinking of:

You could monitor on your mobile device or computer, or request a notification when a meteorological threat looms.  You could receive warnings and recommendations for personal actions to save lives or property.

Since your device knows your location, information and warnings could be specific to your position.

Some of you may know that the UW has already built components of such a system.   For example, there is Seattle SnowWatch:

And Seattle WindWatch:

To build a comprehensive environmental monitoring and forecasting system for Seattle, King County, or other locations is quite possible and could save many lives and prevent property damage.

If heavy rains were expected at your location, you could attend to drains and gutters, avoid sleeping in the basement, and evacuate potentially flooded areas.   Cities could bring in staff to clear drains.  

For cold waves, homeless folks could be required to move inside (there have been too many deaths in Seattle from exposure in the past several years).    For strong wind events, folks could avoid sleeping when trees could fall and prepare for outages.  City Light could pre-position crews and resources.

You get the idea. 

With highly skillful and site-specific warnings, society could make better decisions and greatly reduce the impacts of strong local weather events.  The number of people injured or killed by severe weather could be greatly reduced with the proper application of the amazing forecast skill available today.

Western Washington and Oregon Wildfires are Most Frequent This Time of the Year: Should We Worry?

Climatologically, the most costly meteorological disaster west of the Cascade crest occurs at this time of the year:  massive wildfires associated with strong easterly winds.

Here is a map of the big ones through 2020

And here are their dates, areas, and direct fatalities.  Late August and early September are the favored times.

Why late summer?    

One reason is that surface fuels are relatively dry after our warm, near-rainless summer.  But even more important, early September is a period when western Washington and Oregon can experience very strong, very dry easterly winds.

It is really hard to get big fires in the west when cool, moist air floods western Oregon and Washington.  Strong easterly winds (from the east) are very dry, starting in eastern Oregon and Washington.  They dry even more as they descend the western slopes of the Cascades.

During the late summer and early fall, high pressure can build inland (associated with cold, dense air moving southward out of Canada).   See example below.

With high pressure inland and lower pressure along the coast, offshore-directed easterly winds develop, as illustrated by the winds at 850 hPa (about 5000 ft) at the same time.

These easterly winds, and the accompanying dry air, can start and maintain fires, such as the huge Labor Day fires of 2020.

I know your next question: will this happen this year?  

I have very good news.  It has not happened yet, and model forecasts do not suggest that this pattern will set up during the next two weeks.   After that, the threat declines rapidly.

To show this, here is the forecast for meteorological conditions at Stampede Pass in the central Cascades.  No strong easterly wind periods.  Other mountain sites are similar.

Major fires on the western side of the Northwest can easily run into the billions of dollars and result in many injuries and deaths.

What about climate change?  Will that make such fires more frequent?  

Published research (some done by my group) has found that global warming will cause a DECLINE in widespread wildfires.

That is not a typo.  A DECLINE. 

Why?  Because global warming preferentially warms the interior of the continent, with the less dense, warmer air weakening the interior high pressure that drives easterly flow

Announcement

I will be teaching Atmospheric Sciences 101 this autumn if anyone is interested.  It provides a good general intro to meteorology and weather prediction.  It will be hybrid, both in person (MUCH, MUCH BETTER) and online.  Information is found here: 

https://a.atmos.washington.edu/~cliff/ATMS101Y2026.html

Tropical Storms Invade Hawaiian Waters: The Role of El Nino

Normally, tropical storms and hurricanes avoid the area of the Hawaiian Islands.  

Why?   Because the nearby Pacific is usually too cool!  

In general, surface temperatures must reach at least 80°F (26.5°C) to sustain tropical storm development.

This year, due to a very strong El Nino, temperatures south and east of Hawaii are 1-2 C above normal (see map of differences from normal for sea surface temperature)

As shown by a more detailed, close-in map, the 27C line just reaches Hawaii.    A "warm enough" bath is open.

No wonder tropical storms can approach Hawaii this year!

The effects of the warm water have been dramatic.

Consider satellite imagery from yesterday afternoon...and be prepared to be impressed!

A high-resolution satellite image shows three hurricanes/tropical storms over the eastern Pacific, with a red arrow pointing to the Big Island.  Wow.

Here is an infrared image of the storms.   Amazing.

Even more amazing is a series of forecast maps of evolution of the tropical storms.  I will show you maps of atmospheric moisture through depth.

Today at 11 AM, the swirls of moisture around three tropical storms are evident.  Stunning.

On Saturday morning, they are still there, with one storm passing south of the Hawaiian island

On Sunday morning, the western storm starts moving northeastward towards Hawaii!  Some moisture from the eastern storm extends into southern California, which is going to get some rain as a result

Now the most amazing thing.   The two eastward storms start to interact on Monday.

Then the combined system starts to move northwest on Tuesday.

The storm's crazy movement near Hawaii is reflected in the total precipitation over the next 10 days. You can see the northward jog, followed by a turn to the east.     Quite unusual!

A great time to visit Kauai if you are meteorologically inclined. 😊