Strong winds and rain expected over the weekend could hamper the efforts of California firefighters to battle a week-old wildfire that has become the largest in the state so far this year.
The weather system is forecasted to bring cooler temperatures and precipitation – from a quarter of an inch (0.63cm) to more than 1in (2.54cm) of rainfall over several days – to the Mosquito fire, which is raging about 110 miles (177km) north-east of San Francisco.
But stronger winds are also expected to arrive in the area beginning Saturday and the winds could throw burning embers and create spot fires despite the rain.
“That’s a bit of a mixed blessing here,” fire behavior analyst Jonathan Pangburn said on Thursday.
The forecast came as firefighters again prevented and flames from entering a mountain town reported major progress on Thursday. Crews on the ground built up containment lines while water-dropping helicopters knocked down hotspots.
Conditions on the ground on Thursday were “looking a whole heck of a lot better”, according to fire spokesman Scott McLean.
“It’s looking really good on the west end where we had that dramatic increase of fire earlier this week,” McLean said on Thursday. Flames raced up a drainage ditch into a neighborhood, but firefighters saved all the homes.
Scientists say climate change has made the west warmer and driver over the last three decades and will continue to make weather more extreme and wildfires more frequent and destructive. In the last five years, California has experienced the largest and most destructive fires in its history.
Evacuation orders remained in place for some 11,000 residents because of the unpredictable nature of the winds, McLean said, which typically blow in the direction of several canyons and could rapidly spread flames if gusts pick up.
The Mosquito fire was 20% contained after destroying at least 70 homes and other buildings. Total containment of the fire is expected to occur around 15 October.
The nearly 106-sq-mile blaze on Wednesday surpassed the size of the previous largest conflagration in 2022 – the McKinney fire – although this season has seen a fraction of last year’s wildfire activity so far.
Meanwhile in southern California, dogs aided the hunt for a person missing in a heavily damaged area of the San Bernardino Mountains where thunderstorms unleashed rocks, trees and earth that washed away cars, buried homes and affected 3,000 residents in two remote communities. Nearly 2in (5cm) of rain fell Monday at Yucaipa Ridge between Oak Glen, home to apple orchards that are a fall tourist destination, and Forest Falls, once a summer getaway for cabin owners that has become a bedroom community.
“This entire area is blanketed with up to 6ft (1.83 meters) of mud, debris, large boulders” said Jim Topelski, a San Bernardino county fire chief.
The mudslide damage in Oak Glen and Forest Falls served as a powerful warning to residents of the lingering damage wildfires can cause months or even years after flames are extinguished and the smoke clears.
An intense amount of rain even over a short period of time can have catastrophic effects on hillsides where fire has stripped vegetation that once held the ground intact.
In addition to the Mosquito fire, two other large fires are burning in the state.
The Fairview fire was burning about 75 miles south-east of Los Angeles. The 44-sq-mile blaze was 84% contained on Thursday. Two people died fleeing the fire, which destroyed at least 35 homes and other structures in Riverside county.