The raging Oak fire burning near Yosemite national park has forced the evacuation of more than 3,000 people and offered an alarming look at what could be another devastating year for wildfire in California.
The state had been experiencing a slower start to the traditional fire season, but the Oak fire – which has exploded to 17,000 acres since breaking out on Friday – appears to have brought an end to that, tweeted Daniel Swain, a climate scientist at UCLA.
Officials have said “exceptional conditions” fueled the blaze and its “unprecedented” behavior, including casting embers more than a mile in front of the main body of the fire.
“The fire behavior that we’re seeing on this incident is really unprecedented,” Jon Heggie, a Cal Fire battalion chief, told CNN. “It’s moving extremely fast and the reaction time to get people out is limited.”
What’s driving the Oak fire?
The Oak fire is the third to burn near Yosemite in recent weeks and is far larger than the Washburn fire, which threatened ancient giant sequoias.
Experts say dry air, strong winds, parched trees and grass and soaring temperatures caused the Oak fire to expand rapidly through the rugged foothills in recent days. The area has experienced nearly two weeks of triple digit temperatures and low humidity. Vegetation is at almost record levels of dryness.
All this comes at a time when the state is seeing increasingly destructive and deadly blazes and the climate crisis creates conditions ripe for destruction.
“There was some decent wind yesterday, and we’re in a 1,200-year drought,” Daniel Patterson, a Sierra national forest spokesperson, told the Sacramento Bee over the weekend. “And all that is the perfect recipe for extreme fire behavior. We have been seeing this in California in recent years.”
It’s also burning through an area that hasn’t seen fire since 1924 and is filled with dense vegetation, Crystal Kolden, a pyrogeographer at the University of California, Merced, said on Twitter.
#OakFire is blowing up rn due three main factors: fuel load, heat, and very dry air (relative humidity). 108F today, RH only rose to 35% last night and was 5% at El Portal an hour ago. Area hasn't burned since 1924 per https://t.co/Xle0LioiNN pic.twitter.com/t9gzjx7MH5
— Dr. Crystal A. Kolden 🔥 (@pyrogeog) July 23, 2022
The fire managed to spread significantly in nearly every direction, burning aggressively up and down slope, Swain said in a tweet, pointing to the heavy fuel load and extreme drought as factors.
What does the climate crisis have to do with it?
California has always burned – the landscape is adapted for flames. Before European colonization, Indigenous people in North America carefully managed the land and intentionally set fires. Those efforts and blazes sparked by lightning burned as many as 4.5m acres of the state each year.
But as the climate emergency brings rising temperatures, California has become increasingly vulnerable to extreme wildfires. In 2020 and 2021, the state saw two of the most devastating fire seasons on record, with more than 6.8m acres burned and 36 deaths.
At the same time the state has been plagued by a grueling drought that experts estimate is the driest 22-year stretch in at least 1,200 years. Drought is not unusual for the state, which has historically faced wet years interspersed with dry years, but the climate crisis is compounding this and intensifying drought conditions.
The climate crisis is causing more heatwaves. As the arctic warms faster than the rest of the globe, there is less and less difference between temperatures in the north and closer to the equator. This leads to swings in the North Atlantic jet stream and, in turn, extreme weather events such as heatwaves and floods, according to Jennifer Francis, a senior scientist at the Woodwell Climate Research Center.
These hot and dry conditions cause fires to spread more quickly as heat removes moisture from vegetation and creates fuel.
How bad will California’s fire season get this year?
The National Interagency Fire Center (NIFC) has forecast that California will be hit hard by fire conditions in the coming months.
California fire officials reported last month that vegetation was already as dry early in the summer as it would typically be in October, a foreboding sign.
“It is dire across the board,” Dr Craig Clements, the director of the Wildfire Interdisciplinary Research Center at San Jose State University, told the Guardian last month. “We have a lot of accumulation of dead fuels and because of drought it is just going to get worse and worse. We can only expect as we get later in the summer, that the fires will get bigger.”
Reuters contributed to this report
