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Capital Weather Gang

How climate change is making disasters like the Carr Fire more likely

July 30, 2018 at 2:07 PM

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Officials said the Carr Fire in Northern California, which started July 23 and has tripled in size, was caused by a mechanical issue involving a vehicle. (Allie Caren/The Washington Post)

Firefighters are waging war against 17 wildfires that cover 200,000 acres in California this week. Front-line dispatches suggest that, at least at times, they’ve lost the battle. The bodies of two children were found under a wet blanket with the remains of their great-grandmother hovering over them. Three firefighters and one bulldozer operator are dead. More than 700 homes have burned to the ground.

Crews have struggled, at least in part, because they have never seen fires behave like this before.

“What we’re seeing in California right now is more destructive, larger fires burning at rates that we have historically never seen,” Jonathan Cox, a Cal Fire spokesman, told CNN on Monday morning. “And our message is simply, if you feel like you could be in danger, to leave the area when these fires are burning.”

The most destructive wildfire in California, the Carr Fire, went from a manageable blaze to a “war zone” overnight. On Wednesday morning, the Carr Fire was 4,500 acres and 24 percent contained, according to Cal Fire. By Thursday morning, it had exploded to 20,000 acres and 10 percent contained.

Several specific conditions are feeding the inferno. Afternoon temperatures have peaked in the triple digits around Redding, Calif., since early last week. On Wednesday, the high was 107 degrees. At the same time, winds that were persistent but manageable earlier in the day picked up, gusting to 21 mph. The dew point — a measure of how much moisture is in the air — dropped precipitously through Thursday afternoon until humidity was 10 percent as the temperature reached 110 degrees.

On top of that, the soil in Northern California is exceptionally dry. A hotter-than-average summer and a very dry winter have led to tinder-dry vegetation. When it ends Tuesday, this month will become Redding’s hottest July on record, with an average temperature of 86.7 degrees. The energy release component, or how much fuel is available for the fire, is at the highest it has been around Redding since at least 1979.

The Northern Hemisphere is warming faster than the planet as a whole, according to the World Meteorological Organization. “That heat is drying out forests and making them more susceptible to burn. A recent study found Earth’s boreal forests are now burning at a rate unseen in at least 10,000 years.”

As Earth’s average temperature warms because of human-made climate change, topsoil will continue to dry out, according to the 2017 National Climate Assessment.

“The incidence of large forest fires in the western United States and Alaska has increased since the early 1980s,” the assessment concluded with high confidence, “and is projected to further increase in those regions as the climate warms.”

What remains a critical question is how climate change affects the winds that cause wildfires to spread.

A plane drops fire retardant as firefighters continue to battle a wildfire in the Cleveland National Forest near Corona, Calif. Firefighters are working in rugged terrain amid scorching temperatures that have prompted warnings about excessive heat and extreme fire danger for much of the region.
This satellite image released by NOAA shows the wildfires, known as the Mendocino Complex, in Northern California.
A home was damaged by the Ranch Fire near Clearlake Oaks, Calif. The River and Ranch fires are part of the Mendocino Complex Fire.
Utility company personnel work on damaged power lines near Clearlake Oaks.
Mailboxes of evacuated residences are tagged on a road near Clearlake Oaks.
A plume of smoke, from a wildfire burning near the Holy Jim area, looms in the distance over Lake Forest, Calif.
A hot spot flares along High Valley Road in Lake County.
This still image taken from a video obtained from social media shows the Trabuco Canyon as a tanker aircraft dumps a load onto Holy Fire near Santiago Peak, Calif.
The Ranch Fire spots out ahead of the main fire in Spring Valley, burning two homes.
The Ranch Fire spots out ahead of the main fire in Spring Valley.
Smoke rises Monday from the Holy Fire in Cleveland National Forest in Southern California.
Crystal Easter, of Spring Valley, comforts her dogs after they evacuate a blaze.
Evacuees from Lucerne, from left, Ken Bennett with Ember Reynolds, 8, and Lisa Reynolds watch the sunset as smoke from the Ranch Fire rises into the sky at Austin Park Beach in Clearlake.
Smoke rises from the Holy Fire in Cleveland National Forest, in Southern California’s Lake Elsinore.
An Air Force plane drops fire retardant on a burning Clearlake Oaks hillside in Lake County.
Firefighter Joe Smith retrieves supplies while battling the fire near Clearlake Oaks.
Embers smolder along a hillside.
A deer flees from flames.
Ventura County firefighters including Caleb Amico, foreground, watch as a helicopter makes a drop on a hot spot of a wildfire in Scotts Valley near Lakeport, Calif.
Debbie Prior leads a horse out of Clearlake Oaks.
A firefighter walks around a swimming pool sprayed by Phos-Chek fire retardant after a 747 Supertanker plane made a pass while fighting a wildfire near Lakeport.
A 747 Supertanker makes a drop in front of advancing flames from a wildfire in Lakeport.
Flames from a wildfire advance down a hillside, towering over homes off Scotts Valley Road, near Lakeport.
A tower of smoke pours from Cow Mountain as California firefighter Bob May keeps watch on surrounding vegetation for spot fires during a wildfire off Scotts Valley Road, near Lakeport.
A hilltop home west of Lakeport is in ruins.
A burned pickup truck was destroyed west of Lakeport.
Monterey County Fire Capt. John Hasslinger, left, and firefighter Patrick Tacheny, right, are seen early Wednesday morning at the Ranch Fire in Mendocino County.
Firefighters from Brea cut fireline in support of an operation at the Ranch Fire.
The Ranch Fire has destroyed 10 homes and one structure, according to Cal Fire.
Cal Fire firefighters extinguish flames as the River Fire advances toward structures off Hendricks Road, west of Lakeport.
An outbuilding and a barn burn west of Lakeport.
A barn and grass burn around a parked BMW sedan, west of Lakeport.
A Shasta County firefighter stumbles after water pressure to a fire hose is turned on while fighting the River Fire, west of Lakeport.
The Mendocino Complex burns near the Mendocino National Forest and Highway 20 northwest of Lakeport.
The Mendocino Complex burns late Monday evening off Highway 20 west of Lakeport.
Cal Fire firefighters patrol a property threatened by the Mendocino Complex off Highway 20 west of Lakeport.
Fire burns near debris and a telephone pole off Highway 20 at the Mendocino Complex.
A Cal Fire firefighter keeps flames from a firing operation in check off Highway 20 west of Lakeport.
A fire supervisor truck observes fire behavior as the Mendocino Complex burns past Scotts Creek Road near Lakeport.
Firefighters from local government agencies in Los Angeles County monitor fire behavior off Highway 20 northwest of Lakeport.
The sun sets amid smoke from the Mendocino Complex near Lakeport.
A firefighter walks along a containment line while battling a wildfire in Redding.
A vintage vehicle is seen through the devastation brought by fires near Mountain Center.
Tucker Zimmerman stands next to the trailer he has used to rescue scores of horses left behind in evacuated areas from the Carr Fire in Shasta County, west of Redding, Calif.
A helicopter prepares to drop water on the blaze.
Homes leveled by the Carr Fire line the Lake Keswick Estates area of Redding.
A firefighter uses a hose to douse hot spots while battling the Carr Fire burning along a highway near Whiskeytown, Calif.
Trees burn with flames from the Carr Fire near Whiskeytown.
Firetrucks pass by approaching flames from the Carr fire near Whiskeytown.
A woman surveys damage to her grandmother's house after the Carr Fire burned through Redding.
Helicopters drop water on hot spots of the Carr Fire burning in the hills west of Redding.
Wade Brilz looks at what remains of his Redding home, which was destroyed by the Carr Fire.
Charred cars bear testament to the Carr Fire’s destructiveness in Redding.
A firefighter uses a drip torch to light a backfire while battling the Carr Fire in Redding.
A woman hoses down a building in Whiskeytown as the Carr Fire burns in the distance.
The husks of boats burned by the Carr Fire remain on a lake in Whiskeytown.
The Carr Fire burns along Highway 299 in Shasta, Calif.
A structure burns as the Carr Fire races along Highway 299 near Redding.
A home and car damaged from the Ranch Fire near Clearlake Oaks, Calif.
Photo Gallery: Fueled by scorching temperatures, dry air and unpredictable winds, the Carr Fire has forced thousands to flee, torched 500 buildings and killed two firefighters.

Because of the Carr Fire’s proximity to homes, officials started ordering evacuations almost immediately. By Tuesday morning, three communities had been told to leave their homes and make camp in schools turned shelters. Since Thursday, dry winds have fanned the flames of the Carr Fire, spreading it across 100,000 acres. Thousands of people have evacuated. More than 700 homes have been destroyed, and the fire still threatens 5,000 structures, officials said.

If you ask the crews on the ground, they will tell you it’s not just the hot and dry weather that’s making fires worse. Firefighters have noted recently that fires are behaving differently than they did in the past. For decades, officials depended on a tried-and-true process to prevent wildfires from spreading: fight them from downhill. Fires naturally expand uphill because heat rises, creating uphill winds, and because the lapping flames extend upward, making uphill grass the easiest target.

But KQED reports that firefighters say that process isn’t working as well anymore — the Carr Fire being an example — and no one has a clear explanation as to why. It could be drought conditions, increased fuel load or warmer overnight temperatures that spur evening winds.

“Is that a statistically significant trend?” asked Nick Nauslar, a fire weather forecaster at the National Weather Service in Oklahoma, in an interview with KQED. “And if so, what might be causing that? There would have to be a couple more steps before I try to make assumptions or formulate theories on why that might be happening.”

It is not resolved how climate change might shift or strengthen winds that blow wildfires downhill into mountain communities. But after wildfires in Greece killed more than 80 people, the World Meteorological Organization highlighted micro-scale winds as a key wildfire forecasting problem.

In Northern California, officials are making progress on the Carr Fire, which was 20 percent contained as of Monday morning. The temperature will continue to hit or surpass 100 degrees through the end of the week in Redding, with no rain in sight.

Angela Fritz is an atmospheric scientist and The Washington Post's deputy weather editor. Before joining The Post, Fritz worked as a meteorologist at CNN in Atlanta and Weather Underground in San Francisco. She has a BS in meteorology and an MS in earth and atmospheric science.

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