‘Heat dome’ coming to California brings new challenge for wildfires

Another round of dangerous, triple-digit heat is set to hit much of interior California this weekend, creating new concerns for firefighters battling wildfires across the state, two of which have already burned more than 15,000 acres.

“More dramatic warming will begin on Friday as a large, warm upper trough expands westward across the central portion (of the country),” the National Weather Service wrote in its bulletin Wednesday morning. ForecastAn upper-level ridge of high pressure—colloquially called a heat dome – The San Joaquin Valley and Southern California deserts will be most directly affected, but temperatures are expected to rise across nearly all parts of the Golden State this weekend.

Joe Sirard, a meteorologist with the National Weather Service in Oxnard, said the Los Angeles area will remain on the western edge of the system as it moves southwest before dissipating to the north and west — creating significant “compression heating” beneath the ridge of high pressure. Sirard saidheat dome” There is no precise meteorological term, but it describes the process that raises temperatures as air sinks beneath an upper ridge.

“This will help to increase the heat,” Sarard said. “The hottest weather should be in the desert, the San Joaquin Valley and inland valleys — away from the coast.”

Something similar is expected to happen in the interior areas of California. Risk of moderate or severe heat on Friday, Saturday and Sunday, and in some areas through at least Tuesday. “Dangerously hot conditions” are expected in the San Joaquin Valley and Sierra Nevada foothills, including monitor extreme heat It will be in effect from Saturday through at least Monday, when temperatures could reach 110 degrees.

The South is expected to have its hottest day on Saturday, when temperatures will reach the 90s in the Los Angeles County valleys while temperatures in the desert and lower mountains will reach the mid-100s.

“It will stay a few degrees above normal for the most part through Wednesday next week,” Sarard said. “The coast will be largely unaffected, however, as the upper ridge remains to the east, and this system could actually strengthen the marine layer by the weekend.”

Rising temperatures are already a concern for firefighters, as the incident comes just days after strong winds fanned the flames of the Post Fire, which broke out Saturday near Gorman in northern LA County and quickly grew in size.

“Whenever the weather gets hot, … obviously that’s going to be a driving force for the spread of fire,” said Jonathan Torres, a spokesman for the Los Angeles County Fire Department. “Obviously that makes it very difficult for crews doing hand-to-hand combat.”

According to fire officials, the Post Fire was 39% contained as of Wednesday morning and appeared to have grown to 15,690 acres. After several days of dangerous red-flag conditions — high winds and low humidity — firefighters were able to make “substantial progress” Tuesday night, according to a report. wednesday morning update,

“Weather conditions were favorable last night and allowed crews to raise control lines,” the update said, adding that a “significant warming trend” was expected to begin Thursday into the weekend. Winds were expected to gust up to 20 mph on Wednesday, which wasn’t too strong, but was dramatically weaker than what crews had experienced the past few days.

Because of the dangerous conditions and steep climb, fire officials continued to work tirelessly. Transporting staff by boat across Lake Pyramid On Wednesday, aircraft were allowed direct access to the fire while Air Force personnel worked from above.

In northern Colusa County, the Sites fire had grown to 15,565 acres by Wednesday morning, nearly matching the Post fire in size, which recently became the state’s largest blaze. Biggest wildfires of the yearThe Sites fire is only 5% contained, according to the California Department of Forestry and Fire Protection.

Fire officials there hoped to make significant progress Wednesday and Thursday — while strong winds abated and temperatures remained high.

“It’s going to be very hot this weekend, with temperatures above 100 degrees for possibly four or five days,” Mark Marcucci, chief of Cal Fire’s Sonoma-Lake-Napa Unit, told crews at the Site Fire. morning Briefing“So what I’m asking you to do today is keep up your good work, and see what we can do to minimise the number of people we need to bring in over the weekend.”

Communities near the Post and Sites fires are still under evacuation orders, and dozens of buildings remain at risk.

Across the state, at least two other major wildfires are still active: the Point Fire in Sonoma County, which was 50% contained Wednesday and had burned 1,207 acres, and the Aero Fire in Calaveras County, which grew to 5,425 acres Wednesday and was 33% contained, according to Cal Fire.