Santa Ana winds and low humidity trigger an elevated fire risk in Southern California

Jan. 28, 2018 5:15 PM PT

A combination of strong, gusty winds and low relative humidity will raise the risk of fire danger in Southern California through Monday afternoon, according to the National Weather Service.

A red flag warning went into effect Saturday night and will remain in place until 3 p.m. Monday, as warm Santa Ana winds blow through the region.

In the Santa Monica mountains, forecasters expect 30-to-45 mph winds, with gusts up to 70 mph. The coastline will see 20-to-30 mph winds, with gusts up to 45 mph, while the Santa Clarita Valley could see gusts of up to 50 mph.

“The strongest gusts are in the canyons and valleys of the mountains because they get funneled as they go through,” said Kathy Hoxsie, a meteorologist with the weather service. “They’ll be strongest in the evening, so overnight they should go down a little bit.”

Sunday brought very low relative humidity, in the single digits in some areas, as temperatures climbed into the 80s, with the trend expected to continue on Monday, forecasters said.

Some areas saw record-breaking heat Sunday. A high temperature of 90 degrees was recorded in Long Beach, breaking the previous record of 88 degrees set in 1976, Hoxsie said. In Burbank, the temperature reached 86, breaking the old record of 85 degrees also set in 1976.

“It’s very dry — far below normal for this time of year, but it’s also kind of typical with a Santa Ana winds condition,” said David Sweet, a meteorologist with the National Weather Service in Oxnard.

The Santa Ana winds are fueled by air moving from high pressure zones in the Great Basin area of Utah and Idaho to lower pressure zones along the Southern California coastline.

Strong winds could potentially push a fire along, helping it to spread quickly, while low relative humidity allows vegetation to burn readily.

The red flag warning is not a predictor for fires, Sweet said, but it does raise concern for rapid fire growth.

UPDATES:

5:15 p.m.: This article was updated with new information from the National Weather Service about the wind forecast and record-breaking heat.

This article was originally published at 8:35 a.m.