A massive heat wave across inland California is expected to send temperatures into the triple digits this week, raising the threat of wildfires and raising concerns about health risks.
“We’ve got a long stretch of very warm temperatures that will build through the week,” said Ariel Cohen, a meteorologist at the National Weather Service in Oxnard.
According to the weather service’s Monday forecast bulletin, this warming trend will “allow for dangerous heat through the week,” when temperatures rise from San Luis Obispo County down to the San Diego County border. A widespread heat advisory has been issued for most of the region until Friday, except for coastal cities.
Starting Tuesday morning, an extreme heat watch will go into effect, with officials warning of “dangerously hot conditions with temperatures as high as 95 to 105.”
“There is a high risk of dangerous heat illness for anyone, especially for the very young, the very old, those who do not have air conditioning, and those who work outside,” said the heat advisory.
Highs on Wednesday, far from the coast, will range from 90 to 105 degrees across much of the region, health officials warned. In Los Angeles County, the San Fernando Valley will likely see the highest temperatures, with the Woodland Hills expected to reach 110 degrees Wednesday. The Antelope Valley could also reach 110 degrees, while Santa Clarita will be behind at 105 or 106 degrees, forecasters said.
Low temperatures across the region will likely stay in the 70s even overnight, providing little relief and increasing health concerns.
A parallel pattern that brings monsoonal moisture to the region is expected to increase humidity as temperatures rise, “which will make the effect of the heat much worse,” Cohen said. He urged people to stay hydrated, avoid outdoor activities during the heat of the day and be aware of the signs of fatigue and heatstroke.
That humid pattern is also expected to produce showers and thunderstorms in the mountains, which will increase the likelihood of fires starting from lightning strikes.
In 2020, a series of thunderstorms in mid-August tore through California, sparking thousands of dry lightning fires. By year’s end, it was the state’s worst wildfire year in modern history, with more than 1.4 million acres burned.
Cohen said the moisture that usually accompanies those storms should keep fire danger low. However, higher winds expected late Wednesday in many interior mountains, including in Los Angeles, Ventura and Santa Barbara counties, will likely elevate fire conditions and could cause the fire to grow faster if one starts, Cohen said.
However, Southern Californians aren’t the only ones who will be looking for ways to escape the heat this week.
According to the National Weather Service’s Hanford station, areas from the mid-coast to the Sierra will be under a heat advisory through Thursday. As monsoonal moisture passes, there is a 30% chance of thunderstorms in the high desert and a 10% chance of dry lightning, the station said in its Monday forecast. There will be moderate to severe heat hazards on Tuesday and Wednesday.
Far north in the Bay Area, residents should expect temperatures in the 90s and hot spots hovering in the 100s with no relief from the heat overnight, the National Weather Service said. While the Sacramento Valley won’t get hot enough to issue a heat advisory, there will be elevated fire conditions in the mountains, where isolated thunderstorms, dry lightning and gusty winds are possible, said Bakari Anderson, a meteorologist with the National Weather Service in Sacramento.
As the summer heat sets in across the region, fires have begun to appear.
On Saturday, the fire started in Sierra County and had grown to more than 6,400 acres by Monday, according to the California Department of Forestry and Fire Protection. The Ndlovu fire was contained by 5% in the afternoon.
Two fires were reported on Sunday and a new fire was reported in Shasta County on Monday, according to the Cal Fire website.
In Southern California, several wildfires have recently broken out, prompting evacuations near Lake Piru and the Antelope Valley. The latest incident, the Summit fire, has already destroyed at least one home and damaged three others, according to the Los Angeles County Fire Department, but officials say its progress has been halted.
The fire, however, was only 31 percent contained as of Monday, and was expected to continue to burn in hot conditions as conditions continued to be hot and windy, officials said. It burned about 2,700 acres near the Los Angeles-San Bernardino county line.
Increasing heat and wind could pose a challenge to ongoing firefighting, weather service officials warned, and would likely complicate the start of new fires.
