Los Angeles’ ‘unusual’ drought keeps risk of new fires high. Rain is desperately needed

Winds are expected to continue to dissipate this week, but it looks like a short reprieve for fire-ravaged Southern California.

There is a growing risk that significant fires will return to Los Angeles and Ventura counties starting early next week. But even more than the winds, the region faces the danger of extremely dry conditions and a lack of rain.

“It really is a broken record. Although Santa Ana winds are common and normal for this time of year, it is not normal to be this dry,” said Alex Tardy, a meteorologist at the National Weather Service office in San Diego. “Normally, between Santa Anas, you’ll have at least one rain and one Pacific storm in an average year, and we don’t even see that.”

Southern California is experiencing one of its driest starts to winter on record. Much of the region received only 5% or less of its average precipitation for this time of the water year, which began Oct. 1, Tardy said.

Downtown Los Angeles has received just 0.16 inches of rain since Oct. 1, which is 3 percent of the average at this point in the season, which is 5.56 inches.

The record low for this three-and-a-half month period in downtown Los Angeles was in the water year that began October 1, 1903 – when only a trace of rain was detected until January 13 1904, according to data shared by Tardy. The start of the 1962-63 water year was also very dry, with downtown Los Angeles receiving only 0.16 inches of rain on January 13, 1963.

Downtown Los Angeles’ average annual precipitation is 14.25 inches.

For many other parts of Southern California, “this is the driest start to the water year,” Tardy said, “and you can see extreme fire behavior with ignitions.”

In San Diego, only 0.14 inches of rain fell between October 1 and January 14. This is the driest start to a water year in 174 years of record keeping. The previous record for this period was 0.35 inches of rain accumulated between Oct. 1, 1962, and Jan. 14, 1963, according to Miguel Miller, a forecaster with the National Weather Service office in San Diego.

What exacerbates the fire situation is that January is the peak month for Santa Ana winds – powerful winds that develop when high pressure over Nevada and Utah sends cold air toward pressure areas lower along the California coast.

The air dries, compresses and warms as it descends from the high deserts – the Northeast – over California’s mountains and through canyons, drying out vegetation as the wind gusts.

Tardy said the magnitude of the Santa Ana winds is typically strongest in January, but it’s not typical to have such dry conditions at the same time.

Others agreed.

“In my career, I have never seen punitive events in Santa Ana overwhelm the normal winter rainy season to this extent,” said retired climatologist Bill Patzert.

In the coming days, Monday and Tuesday will be the most concerning at this point, with a 70% probability of red flag warnings for Los Angeles and Ventura counties, indicating a high probability of critical behavior in the event of a ‘fire in case of fire, according to the National. Weather service.

“Most importantly, the weather looks very dry all of next week, with an increasing risk of red flag warnings,” said Ryan Kittell, a meteorologist with the Weather Service office in Oxnard.

Relative humidity could fall below 10% next week, meaning vegetation will be particularly dry and vulnerable.

“It almost seems out of this world,” Kittell said.

Regarding the wind, there is increasing confidence in the moderate development of Santa Anas. As of Thursday, forecasters estimated the chance of moderate wind in Santa Ana to be about 40% for Monday and about 60% for Tuesday.

There also remains a small chance of a strong Santa Ana wind.

Next week’s winds are expected to be influenced by an “inland slider” – a type of low pressure system that is expected to move down from Canada into inland California and Nevada and bring high pressure wind over the Great Basin, but not about the rain we desperately need.

The system is called an “inside slider” because “it just slides in, never goes over the water, never gives us that chance to rain,” Kittell said.

The high pressure that will send cold, dry air into Southern California next week is also influenced by frigid air expected to move from the Arctic toward the northeastern United States, Tardy said .

“We’re going to be on the windy, dry side of this cold air,” he said.

Before next week’s winds pick up, there will be a few days of welcome respite from the devastating fires that have razed large areas in and around Altadena and Pacific Palisades, destroying thousands of structures, including many houses.

“So the moral of the story is we’re going to, fortunately, get a break from all of this for the end of this week, but unfortunately it’s going to be short-lived,” Kittell said of the dangerous fires .

An army of firefighters worked for days to keep the Eaton and Palisades fires from growing despite weather conditions that primed the area to burn. The Eaton Fire, which has burned 14,100 acres, was 55% contained Thursday, up from 45% a day earlier.

The Palisades fire, which decimated 23,700 residents west of Los Angeles, was 22% contained, compared to 17% the day before, according to the California Department of Forestry and Fire Protection.

With progress in fighting the fires, residents became frustrated at not being able to return home. More than 150,000 Angelenos remain under evacuation orders and warnings.

Los Angeles County Fire Chief Anthony Marrone said during a news conference Thursday that it will be at least a week before some people can begin returning to their neighborhoods. For others, the wait will be longer.

Authorities are still searching burned properties for additional deaths and have stressed that the areas are rife with hazardous materials, downed power lines and other hazards that make repopulation untenable at this time.

“We’re doing the best we can because we know it’s a challenge for our residents,” Marrone said.

For now, forecasters do not expect to issue an alert indicating an extreme warning signal next week, known as a “particularly dangerous situation.”

The “particularly dangerous situation” warning for extreme fires issued this week peaked around noon Wednesday for the San Fernando Valley, swaths of Ventura County and the Grapevine section of Interstate 5.

Gusts over 30 mph were observed along a traditional Santa Ana wind corridor, extending southwest through places including Palmdale, Santa Clarita, Ventura, Oxnard, Simi Valley and Thousand Oaks.

Wednesday’s winds were about as expected, but Tuesday’s winds were less severe than expected for that day. One potential reason is that the pressure difference between the ocean and deserts wasn’t as strong as the computers predicted, Kittell said.

Another possible reason is that the low-pressure system rotating off the coast — where the Santa Ana winds move westward — wobbled a little further north than expected, Kittell said.

Cut off from the dominant jet stream, this low-pressure system is what is called a “cutoff depression,” which wobbles and can be less predictable than if the system were connected to the jet stream.

Minimum thresholds are so well known to forecasters that they’re nicknamed “meteorologists’ doom,” Kittell said.

Temperatures will remain much cooler than normal in the coming days, with highs Friday reaching just 58 degrees in Redondo Beach, Thousand Oaks and Oxnard; 59 in downtown Los Angeles, Long Beach and Covina; 60 at Canoga Park; and 61 in Santa Clarita.

“The positive thing for our weather concerns is that humidity will continue to climb, especially after (Thursday), with fire concerns decreasing,” Kittell said. With humidity increasing Friday and Saturday, fire concerns are expected to be relatively minimal, although there may be localized gusts between 25 mph and 40 mph coming from the northwest.

The low pressure system off the southern California coast will move in, but there is little chance of rain overnight Saturday into Sunday, Kittell said.

“It will eventually move toward the coast, and all the projections keep it fairly south of Los Angeles County,” Kittell said, “so the chance of rain is very minimal.”

Southern California won’t be much safer from wildfires until heavy rains fall. There is still no significant chance of rain until January 25, according to forecasters.