As a "once-in-a-generation" firestorm has raged across nearly 90,000 acres in Southern California this week—covering an area about six times the size of Manhattan and forcing more than 100,000 people to evacuate their homes—experts are warning how climate change is fueling fires on the West Coast.
LA meteorologist Anthony Yanez tweeted that he has "never seen" the wildfire threat index reach the designation for "extreme," as it did late Wednesday, and quoted Ken Pimlott, director of the California Department of Forestry and Fire Protection, who reportedly told NBC, "There will be no ability to fight fires in these winds."
I've never seen the purple "extreme" threat issued. But this is where we find ourselves Thursday for the #SantaAnaWinds. "There will be no ability to fight fires in these winds." Cal Fire Chief Ken Pimlott #NBC4You pic.twitter.com/2DcBAQxxS0
— Anthony Yanez (@AnthonyNBCLA) December 6, 2017
Environmentalist and 350.org co-founder Bill McKibben indicated the elevated threat warning is a consequence of the "hot new world," a reference to an increasingly warming planet being caused by fossil fuel emissions and other human activity.
For first time ever CA issues its most extreme wind warnings as vast fires rage: “We’ve never used purple before.” Hot new world https://t.co/bMl7dDn58n
— Bill McKibben (@billmckibben) December 7, 2017
Writing for Pacific Standard earlier this week, meteorologist Eric Holthaus notes even though it's still fire season in Southern California, "the current conditions in Southern California seem exceptional." Describing the largest of the region's five fires, he writes:
The Thomas Fire, first identified late Monday night, grew 30-fold in size in just three hours and advanced at a rate of more than an acre per second for 12 hours into neighborhoods in the cities of Santa Paula and Ventura. At the time of the fire, the National Weather Service rated the fire-related weather conditions as "extremely critical," its worst assessment level. Wind speeds near the fire were measured near hurricane force.
"This week's Southern California fires will add to an already disastrous fire season," Holthaus concludes, pointing to wildfires in Northern California that killed at least 44 people earlier this year and are collectively "ranked as the worst fire disaster in California history."
Images and videos from the fires continue to circulate virally on social media, especially from commuters and evacuees on the 405 and 101 highways. Officials were forced to shut down a section of the 101 early Thursday, which the Los Angeles Times reports left "no more open routes between Santa Barbara and Ventura counties."
— Los Angeles Times (@latimes) December 7, 2017
Not the typical morning commute... pic.twitter.com/kJIOQeqsIK
— A. Mutzabaugh CMT (@WLV_investor) December 6, 2017
Daniel Swain, a climate scientist at the University of California Los Angeles and writer of the Weather West blog, was among the group of experts who explained to The Verge how rain is essential to quenching the California wildfires, and how scientists believe climate change has contributed to below average rainfall in the region that is likely to persist into the future.
"By this time of year, usually, there's been some rain that's wetted things down," Swain said, but in the current warm winter dry spell, "it's just as dry as it was in the summer months."
From October to May, strong winds in the upper atmosphere, called the jet stream, typically bring rain storms to California, but National Weather Service meteorologists John Dumas and David Sweet note that so far this year, Los Angeles has seen five percent of its average rainfall, while Burbank has seen even less. In the bottom part of the state, where some areas are enduring a moderate drought, "we're quite parched," Sweet said.
As The Verge reports:
Storms in the jet stream can get diverted by high-pressure bubbles of warm air. A version of this phenomenon called an "atmospheric ridge" is to blame for Southern California's current dry spell. And even bigger one has started forming along the entire West Coast of the U.S. that could shunt rainfall into Canada or Alaska, Swain writes. "We were dry before and now the prospects for rain look even less likely because of the size of this thing," Sweet says.
This is the same atmospheric phenomenon that squatted over the state for three winters in a row during California's record-setting, five-year drought. "The real question is how long it persists," Swains says. During the drought, these ridges lasted for months at a time—but we don't know what's in store for this new one. Even worse news: these atmospheric ridges are getting more common—possibly thanks to human-caused global warming, Swain and his colleagues reported in a 2016 study.
"What should make Southern California fearful is that climate change could mean a future of more frequent and more intense wildfires," the Los Angeles Times editorial board wrote this week. "Today's fires will end, and what we do afterward—assessing how to better prepare, and how and whether to rebuild—will influence the damage from the fires next time."
But even getting to that point—where policymakers can consider taking further steps to address climate change and plan for future fires—has proven difficult, as evacuations continue and firefighters find it difficult to contain the fires due to weather conditions—particularly the powerful Santa Ana winds that are expected to remain strong throughout Thursday.