Tuesday September 8th… Dear Diary. The main purpose of this ongoing blog will be to track United States extreme or record temperatures related to climate change. Any reports I see of ETs will be listed below the main topic of the day. I’ll refer to extreme or record temperatures as ETs (not extraterrestrials).😉
Main Topic: Fire And Ice…More Notes On Wild Western Weather
Dear Diary. The West is under siege from some climate change related weather that is imperiling thousands, particularly from Washington southward through California. Over the weekend we saw hundreds of heat records fall over a good chunk of the U.S. West, which is also in a severe drought. Now the other shoe is starting to drop in our coastal West states where fall Santa Ana and Diablo winds are interacting with near record heat to exacerbate an already historic fire episode.
Strong easterly flow winds are the result of a record cold system diving down through the Rockies and northern Plains producing a drastic weather change. Across portions of the Rockies we literally are seeing record warmth one day and record chill the next.
Thankfully this system will totally end Heatwave Chort sometime by the end of this week, and high winds will die out as thermal gradients relax toward normal levels. Before then though, we will contend with more wild life threatening weather.
For a good report on what has happened over the Labor Day holiday weekend here is a Washington Post article from my good friend Andrew Friedman:
Rare West Coast wildfire outbreak features California Santa Ana wind event
Red flag warnings for ‘critical fire danger’ extend from U.S. border with Canada to San Diego
Pacific Gas and Electric workers stand along Highway 168 as the Creek Fire advances Tuesday near Alder Springs, Calif. (Marcio Jose Sanchez/AP)
By Diana Leonard and Andrew Freedman September 8, 2020 at 9:40 a.m.
California is in the midst of perhaps the most challenging fire year in its history, with yet another dangerous set of weather conditions developing in a state that endured unprecedented heat and explosive blazes over the holiday weekend.
More than 2.2 million acres have burned so far in 2020, surpassing 2018 for the most acres burned annually in the modern record. Three of the state’s four largest wildfires have occurred in just the past three weeks — all over 300,000 acres and not yet fully contained. The Creek Fire in Sierra National Forest, where rescues of trapped hikers and campers are still underway, has ballooned to 143,929 acres in just two days.
But the wildfire threat is not limited to California.
On Monday, blazes broke out amid strong winds and dry air in Washington state. Some of the blazes spread dozens of miles in a single day. Most of the small town of Malden, Wash., located about 35 miles south-southwest of Spokane, was destroyed in one fast-moving blaze.
Wildfire smoke mixed with airborne dust to create hazardous driving conditions and dangerously poor air quality in the state, with widespread road closures in central and eastern Washington. Hazardous air quality due to wildfire smoke has spread across the West, though it will be most concentrated along the West Coast on Tuesday.
On Tuesday, red flag warnings for dangerous fire weather stretched along the entire West Coast from U.S. border with Mexico to Canada, including much of California and Nevada, western Oregon and Washington, along with western Arizona and southern Utah. Strong winds are buffeting areas in and around Seattle and Portland, Ore., with wildfire concerns in both areas. In some places, winds have been strong enough to knock out power. More than 100,000 customers were without electricity in both Oregon and Washington due to high winds Tuesday morning.
Red flag warnings in effect Tuesday for dangerous fire weather. (National Weather Service)
The National Weather Service’s Storm Prediction Center wrote the fire danger was particularly severe in parts of western Oregon and far southwestern Washington state where it described “extremely critical” conditions. Here, the combination of wind gusts over 60 mph, low humidity, high temperatures, and a parched land surface “all suggest continued potential for rapidly moving fire fronts and extreme fire behavior,” the center wrote.
California’s ‘extreme fire behavior’
In this Saturday photo, a burned structure is seen at a wildfire in Yucaipa, Calif. (AP Photo/Ringo H.W. Chiu, File)
The acreage burned in California, while astounding, does not tell the whole story. Fires have been burning in unusual ways this summer, with fire behavior that eludes firefighters’ control. That has allowed them to grow so big, so quickly, without much wind to push them along. Fueled by record-setting temperatures, up to 120-degrees even near the coast, they’ve spawned towering columns of smoke and ash, forming their own thunderstorms and even fire tornadoes.
But the heart of the fire season is still ahead: fast-spreading blazes are most common in autumn, when fierce “offshore” winds blow from inland areas toward the coast.
Those winds have arrived this week, unusually early, on the heels of a record-shattering heatwave. Red Flag Warnings are in place for much of Northern and Southern California, as well as the Sierra Nevada mountains and foothills, as critical fire weather migrates from north to south. The winds threaten to push existing fires into communities, particularly those in the Bay Area, and in Los Angeles, San Bernardino and San Diego counties, which are burning near populated areas.
These winds will transport extremely dry air, with humidity measured in the single digits. This combined with the desiccated vegetation following the heat wave will create rarely encountered wildfire risks.
The California utility PG&E, whose power lines sparked the state’s deadliest wildfire on record that wiped out the town of Paradise in 2018, has begun to implement preemptive power cuts.
In the L.A. area, the biggest immediate fire weather concern is related to the Bobcat Fire, burning in the San Gabriel Mountains just north of Azusa. Forecasters and firefighters are concerned the Santa Ana winds will cause the fire to burn down canyons to nearby foothill communities today and tomorrow.
The U.S. Forest Service has taken the unusual step of closing several National Forests in California due to the extreme fire danger, which puts vast swaths of the state off limits to campers, hikers and other users. Dry, gusty offshore winds are expected in the San Francisco Bay area on Tuesday, with a Red Flag warning through Wednesday morning.
“Needless to say … following a heat wave this set up is not good for fire weather,” the NWS forecast office in San Francisco stated in an online forecast discussion. The offshore wind event is taking place as the state’s second, third and fourth-largest wildfires are still burning, along with a smattering of other blazes, such as the Creek Fire, that ignited and exploded in size this weekend.
The state is just at the beginning of what could be a long offshore wind season, with forecasters expecting warm and dry weather in the months ahead.
“It’s hard to come up with a scenario that is higher risk,” said Noah Diffenbaugh, a professor and climate scientist at Stanford University.
“We haven’t gone into a wind event in California with this many large fires burning. Just from that perspective, we are in uncharted territory,” he said.
Climate change has its ‘thumb on the scale’ of extreme fire
This summer’s fires reflect explosively dry conditions, due to the very dry winter in the northern third of the state, a warm spring that led to rapid mountain snowmelt, and two record-breaking heatwaves in mid-August and early September, among other factors.
According to Diffenbaugh, global warming has its “thumb on the scale” of wildfire — pushing it to extremes as rising temperatures make fuels drier.
The heat is acting on many time scales, from a general rise in temperature to acute heat waves like those immediately preceding the most recent spate of enormous fires.
“Heat waves are breaking records everywhere, and as temperatures soar, so does the speed at which the soil and fuels dry,” Leila Carvalho, a professor of meteorology and climate science at the University of California, Santa Barbara, said in an email.
“What has changed in summer is the frequency and intensity of heat waves, a climatic response to an anthropogenic increase in greenhouse gases that has been predicted [by] climate models [for decades],” she said.
There has also been a broad and statistically significant year-round warming in California since 1895, but especially in late summer and early fall, just when the state is hitting peak dryness and is about to enter its offshore wind season.
Documented increase in dangerous fire days
California’s most destructive and deadly fires have happened in autumn, on the days that dry winds whip across a landscape that hasn’t seen rain in months.
“Rapidly-spreading wildfires are driven by strong gusty winds, and they can be larger, costly and cause many casualties,” Carvalho said.
It is now apparent that Californians must contend with these high-risk days more often.
“Extreme fire weather is becoming more frequent with climate change, and will continue to do so into the future,” Michael Goss, a postdoctoral research fellow in earth system science at Stanford University, said in an email.
Goss is the lead author, along with Diffenbaugh and other climate and wildfire experts, of a study recently published in the journal Environmental Research Letters. It shows that the state’s most dangerous autumn fire weather days, which are more likely to have big, hard-to-control wildfires, have more than doubled in frequency in the last four decades.
Observed trends in autumn mean temperature and mean Fire Weather Index in California.
They define these risky days as those registering the highest (greater than the 95th percentile) readings of the Fire Weather Index (FWI), a fire danger metric that combines a number of different weather measurements, including wind, temperature, and humidity, as well as estimates of plant flammability and drought.
Higher values of the index have been associated with more intense wildfires, as well as more land area burned.
The trend in the FWI coincides with a similar trend in temperature, which has increased by about 1 degree Celsius since 1980, and is likely the main driver here.
“The primary pathway by which global warming affects extreme fire weather is through temperature,” Diffenbaugh said.
But autumn precipitation has also declined in the same time period. In the last several years in particular there simply has not been enough rain in October and November to halt, or at least tame, destructive fire seasons.
Sharp increase in extreme fire weather days by the late 21st Century, under a lower and higher emissions scenario.
The potential for dangerous fire weather is therefore headed upward across many different ecosystems statewide. That trend is expected to continue, although its magnitude will depend on whether and how much we curb greenhouse gas emissions. Without a check on emissions, by the late 21st century some California regions could see as much as 5 degrees Celsius warming, and more than 15 extreme fire weather days each autumn.
New reality of multiple, simultaneous fire incidents
The motivation for the study was the dual fire disasters that unfolded in November 2018, when the deadly Camp Fire raced through the northern Sierra foothills and the town of Paradise, and the Woolsey Fire tore a destructive path across the Santa Monica Mountains in Malibu.
These prolonged, simultaneous events placed substantial burdens on firefighters and communities. Now this is playing out again, except on a larger scale, with firefighters stretched to the limit. According to Cal FIre, 14,000 firefighters are on duty across the state, battling 25 large wildfires.
“Humans are ingenious at managing climate risk, but our systems are built around the historical climate,” Diffenbaugh said. “Systems that were built for the old climate are being stressed in a new way.”
Wildfires have fundamentally changed, but the way we prepare for and manage them has not.
“Managing wildfires in California in a disruptive climate scenario is possible but not simple,” Carvalho said. “Fire management strategies can help but cannot solve the impact of an increase in the frequency and intensity of extreme events, and the consequent disruption of multiple disasters, such as the ones we have observed recently.”
The unprecedented fires this year illustrate the difficulty of adapting as climate goal posts shift.
Diffenbaugh said there is clear evidence that we should be expecting events that fall outside our historical experience. “We’re not yet adapted to the climate change that has already happened, so becoming resilient will require catching up to that change and getting ahead of the global warming that will happen in the future,” he said.
Jason Samenow contributed to this article.
Andrew Freedman edits and reports on extreme weather and climate science for the Capital Weather Gang. He has covered science, with a specialization in climate research and policy, for Axios, Mashable, Climate Central, E&E Daily and other publications. Follow
Just like what I was doing on the Extreme Temperature Diary the last three days, I will be listing notes with linked articles on this dangerous weather situation today in the space below. Newer and more recent items will be added at the top of this list as we roll through Tuesday:
Here are some more of the most recent “ET” reports from Tuesday:
Here is more climate and weather news from Tuesday:
(As usual, this will be a fluid post in which more information gets added during the day as it crosses my radar, crediting all who have put it on-line. Items will be archived on this site for posterity. In most instances click on the pictures of each tweet to see each article. The most noteworthy items will be listed first.)
Now here are some of today’s articles and notes on the horrid COVID-19 pandemic:
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Guy Walton “The Climate Guy”