California Wildfires

Winds Have Diminished and Temperatures Dropped, So Why Is SoCal Still Under a Red Flag Warning?

Humidity levels are a critical component when it comes to the wildfire threat, which will remain high this weekend in Southern California

Powerful bursts of wind, including the infamous Santa Ana gusts, whipped up flames as firefighters fanned out across Southern California to protect communities throughout the week.

Those winds have died down this weekend, but the region remains under a red flag warning, indicating high-risk fire weather. The high fire threat is due largely to extremely low humidity levels in the single digits. 

"It doesn't feel like fire danger is high because you step outside and it's chilly," said NBC4 forecaster Belen De Leon. "The humidity is still very low. It has not recovered.

"Thankfully, the winds are not going to be as strong as they were during the week."

The three main elements of red flag weather are warm temperatures, very low humidity and stronger winds. Temperatures were in the 40s and 50s in parts of Southern California early Saturday. Expect winds of 10-20 miles per hour with isolated gusts to 35 mph.

The humidity level will be down to between 2 and 8 percent, a major reason why there's a red flag warning for mountain areas in Los Angeles County and the Santa Clarita area until 6 p.m. Although wind speeds have decreased, gustly northeast winds will combine with low humidity to create a hazardous situation in those areas, especially on hillsides covered with vegetation that dried out during the dry summer months. 

"The fuel is bone dry, so we have low fuel moisture content and low relative humidity, so you can easily have a topography and fuel-driven fire," said Chief Sam Digiovanna, of the Verdugo Fire Academy. "Make sure you stay on guard. We're still on red flag fire alert."

Firefighters are increasing containment lines around several fires that broke out during a week of low humidity and relentless winds. The Maria Fire in Ventura County had burned more than 9,000 acres. Containment was at 20 percent.

Elsewhere, firefighters are in mop-up mode, watching for flare-ups and hot spots. 

The dry conditions are expected to continue through the weekend. Gusty offshore winds will last through Saturday with peak gusts up to 35 mph in valley and interior mountains of LA and Ventura counties.

Winds weaken late Saturday into Sunday. There's a chance the red flag warning could extended into Sunday.

In Orange County, a red flag warning was to have been in effect through much of Thursday. It was canceled Wednesday night thanks to dramatically weakened winds.

Santa Ana winds, produced by surface high pressure over the Great Basin squeezing air down through canyons and passes in Southern California's mountain ranges, are common in the fall and have a long history of fanning destructive wildfires in the region.

Fall is historically one of the most dangerous times of the year for wildfires in California. Seven of the state's 10-most destructive wildfires occurred in October -- many fueled by monster winds, including Santa Ana gusts. 

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