A Santa Ana wind event that meteorologists expect to be the strongest of the season will begin late Tuesday evening, combining with very low humidity levels and an abundance of dry vegetation to create “extreme” fire weather conditions, including wind gusts of 80 mph in the mountains.
What the National Weather Service is calling an “extreme red flag warning” will be in effect from 11 p.m. Tuesday through 6 p.m. Thursday in much of Los Angeles and Ventura counties. Meteorologists explained that the use of the word “extreme” does not indicate the creation of a new NWS product but, rather, serves to informally emphasize the severity of the conditions expected.
“There is increasing confidence of a strong and damaging Santa Ana wind event late Tuesday evening through Thursday. The peak of the wind event is expected to be Wednesday when damaging wind gusts between 50 and 70 mph will be likely for the wind-pone areas of Los Angeles and Ventura counties, with isolated gusts to 80 mph in the mountains.,” according to an NWS statement. This Santa Ana wind event will likely be the strongest we have seen so far this season.
“These strong winds combined with a long duration of single digit humidities (including very poor to no recoveries Wednesday night) and dry fuels will likely bring very critical fire weather conditions, making this an extreme red flag warning event.”
The red flag warning will apply to the San Gabriel Mountains in Los Angeles and Ventura counties, the Angeles National Forest, the Los Padres National Forest in Ventura County and the Santa Monica Mountains Recreational Area. Northeast winds will blow will blow at 30 to 50 mph in those areas, accompanies by gusts of 60 to 70 mph and possibly 80 mph. The NWS said “slightly weaker” winds are expected Thursday.
“If fire ignition occurs, conditions will be favorable for extreme fire behavior, long range spotting, and very rapid fire spread, which would threaten life and property,” according to the statement. “The strength of the expected winds could result in downed trees and power lines as well as power outages.”
The warning will also apply to the San Fernando and Santa Clarita valleys — areas where northeast winds are forecast to blow at 25 to 40 mph. with gusts of 50 to 60 mph.
In the San Gabriel Valley, beach cities, Metropolitan L.A. and the Hollywood Hills — areas also under the red flag warning — winds of 20-30 mph are expected, along with 50 mph gusts.
Also scheduled starting late Monday and ending Thursday morning is a high wind watch in the same areas covered by the red flag warning.
In the Antelope Valley, a hard freeze watch will be in effect from early Wednesday morning through Friday, with temperatures falling to 18 degrees, according to the NWS.
In light of the forecasted severe winds, Southern California Edison warned that more than 200,000 customers throughout its service area could lose electricity due to so-called Public Safety Power Shutoffs. Under the program, power is cut to transmission lines in danger of being damaged by high winds in an effort to prevent wildfires.
As of early Tuesday afternoon, 74 customers in Los Angeles County were without power due to the program, in Chatsworth and along Angeles Crest Highway.
According to Edison, nearly 56,800 other customers in Los Angeles County are in areas being considered for potential power cuts, including communities such as Santa Clarita, Palmdale, La Crescenta, Calabasas, Malibu, Agoura Hills, Altadena and San Fernando.
Nearly 4,500 customers in Orange County could be affected, in areas such as Irvine, Lake Forest, Orange, Modjeska and Silverado.