3 hours ago
A wind-driven wildfire roared through rural and residential communities north-west of Los Angeles, charring well over 10,000 acres (4,000 hectares) and leveling scores of homes.
The Mountain fire in Ventura county, California, continued to burn on Thursday morning, still at 0% containment, footage shows dozens of structures turned to smoldering ruins, now lining the streets where neighborhoods once stood.
Hundreds of firefighters battled the blaze through the night using both ground resources and helicopters, according to the Ventura county fire department.
Fueled by strong winds with gusts up to 85mph (187km/h) and humidity levels as low as 8%, the fast-moving fire gave residents little time to flee on Wednesday causing frenzied evacuations.
The Santa Ana’s, warm, dry winds that typically whip through southern California this time of year weren’t unexpected. But combined with low humidity, parched grasses – cured in last summer’s heat – and this landscape’s natural tendency to burn the perfect conditions were set for the disaster to unfold.
“The Mountain fire is another sobering reminder that when you combine our natural chaparral landscapes and strong Santa Ana winds with longer, hotter dry seasons, you have all the ingredients for these devastating events to increase in frequency, scale and speed,” said Dr Alex Hall, director of UCLA’s Center for Climate Science, in a statement provided by email. “Unfortunately, it’s never a question of ‘if’ but rather ‘when’ and ‘how big’ when it comes to wildfires in southern California.”
By Thursday morning, the Weather Service reported that relative humidity was as low as 10%, with wind gusts of 60mph in certain areas.
“Any fires that develop will likely spread rapidly,” the Weather Service said on Thursday morning.
The red flag warning will remain in effect in most areas through much of Thursday and will extend into Friday morning for the same regions including the inland empire, the coastal slopes of San Bernardino county, and the mountain areas of San Diego and Riverside county.
But in a Thursday morning update, the NWS said conditions around where the fire is burning “look much improved by Thursday night”.
High wind warnings and dense smoke advisories are in effect for certain regions on Thursday.
Officials from the Ventura county fire department said on Wednesday afternoon that they were aware of numerous structures that had been damaged or destroyed by the fire, but that a more accurate assessment of the damage would be carried out once it was safe to do so.
US wildfire terms, explained
ShowAcres burned
US wildfires are measured in terms of acres. While the size of a wildfire doesn’t necessarily correlate to its destructive impact, acreage provides a way to understand a fire’s footprint and how quickly it has grown.
There are 2.47 acres in a hectare, and 640 acres in a square mile, but this can be hard to visualise. Here are some easy comparisons: one acre equates to roughly the size of an American football field. London’s Heathrow airport is about 3,000 acres. Manhattan covers roughly 14,600 acres, while Chicago is roughly 150,000 acres, and Los Angeles is roughly 320,000 acres.
Megafire
A megafire is defined by the Interagency Fire Center as a wildfire that has burned more than 100,000 acres (40,000 hectares).
Containment level
A wildfire’s containment level indicates how much progress firefighters have made in controlling the fire. Containment is achieved by creating perimeters the fire can’t move across. This is done through methods such as putting fire retardants on the ground, digging trenches, or removing brush and other flammable fuels.
Containment is measured in terms of the percentage of the fire that has been surrounded by these control lines. A wildfire with a low containment level, such as 0% or 5%, is essentially burning out of control. A fire with a high level of containment, such as 90%, isn’t necessarily extinguished but rather has a large protective perimeter and a rate of growth that is under control.
Evacuation orders and warnings
Evacuation warnings and orders are issued by officials when a wildfire is causing imminent danger to people’s life and property. According to the California office of emergency services, an evacuation warning means that it's a good idea to leave an area or get ready to leave soon. An evacuation order means that you should leave the area immediately.
Red flag warning
A red flag warning is a type of forecast issued by the Weather Service that indicates when weather conditions are likely to spark or spread wildfires. These conditions typically include dryness, low humidity, high winds and heat.
Prescribed burn
A prescribed burn, or a controlled burn, is a fire that is intentionally set under carefully managed conditions in order to improve the health of a landscape. Prescribed burns are carried out by trained experts such as members of the US Forest Service and Indigenous fire practitioners. Prescribed burns help remove flammable vegetation and reduce the risk of larger, more catastrophic blazes, among other benefits.
Prescribed burning was once a common tool among Native American tribes who used “good fire” to improve the land, but was limited for much of the last century by a US government approach based on fire suppression. In recent years, US land managers have returned to embracing the benefits of prescribed burns, and now conduct thousands across the country every year.
The fire has already destroyed dozens of homes, according to the Associated Press, and fire officials also reported that at least two people were transported to the hospital for possible smoke inhalation.
“Our firefighters are doing nothing short of heroic out there right now,” Trevor Johnson, Ventura county fire department captain, said on Wednesday.
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Due to the high fire danger, Southern California Edison temporarily turned off power to several thousand customers as part of its public safety power shutoff plan to prevent the electric system from becoming a source of ignition.
Similarly, the Pacific Gas and Electric Company cut power to thousands of accounts across the state in an attempt to limit the risk of ignitions.
As of Thursday morning, about 3,000 customers were without power in Ventura county and just over 500 were without power in Los Angeles county, according to poweroutage.us.
Ventura county schools also announced that all schools in the area would be closed on Thursday and Friday.
Gavin Newsom, California’s governor, announced on Wednesday that the state had secured federal assistance from the Federal Emergency Management Agency to help ensure the availability of vital resources to Ventura county.
“This is a dangerous fire that’s spreading quickly and threatening lives,” Newsom said. “State resources have been mobilized to protect communities, and this federal support from the Biden-Harris administration will give state and local firefighters the resources they need to save lives and property as they continue battling this aggressive fire.”
As the climate crisis turns up the dial, creating new hazards and higher risks for disasters like the Mountain fire, scientists are hoping lessons can be learned.
“Until now, much of the research around managing wildfire risk in California has focused on forested areas, but the Mountain fire once again drives home the urgent need for strategies tailored to the unique landscape, climate and communities of southern California,” Hall said.
“We hope that our work can provide policymakers with the solutions-oriented research they need to make the best decisions to protect our communities and our environment in the face of a changing climate.”
