A powerful storm will treat the Southland to another round of moderate to heavy rainfall Thursday, making flash flooding along with mud and debris flows likely down slopes stripped of vegetation by wildfires, forecasters said.
A flash flood watch is in effect for all of Santa Barbara and San Luis Obispo counties and parts of Ventura County through Thursday afternoon and several areas of Los Angeles County — the San Gabriel and Santa Monica mountains; the San Gabriel, San Fernando and Santa Clarita valleys; L.A. County Beach cities, metropolitan L.A. and the Hollywood Hills — through Thursday evening.
“Rainfall rates between 0.33 and 0.66 inches per hour will be likely between 10 am and 8 pm today, with local rates up to one inch per hour possible near thunderstorms,” warned an NWS statement issued early Thursday morning. “Rainfall of this intensity can produce dangerous mud and debris flows near recent burn areas.”
Thursday’s rains could amount to between three-quarters and an inch-and-a- quarter of rain in valley and coastal areas and between 2 and 4 inches at higher elevations, said National Weather Service meteorologist David Sweet, adding that the storm has lived up to expectations so far and should have its peak day in L.A. County Thursday.
At Palmdale Airport, 0.55 inch of rain fell Wednesday, beating the old May 21 record of 0.54 inch set in 1947.
A flash flood watch will be in force from 6 a.m. through 3 a.m. Friday in both coastal and inland Orange County, where peak rainfall rates of one- half inch per hour are possible, according to NWS forecasters.
Also possible through Thursday evening are thunderstorms off the Southland Coast.
“Any thunderstorm that forms will be capable of producing locally gusty winds and rough seas, dangerous lightning, heavy rainfall with reduced visibility, and waterspouts,” warned an NWS statement that urged sailors to listen to the latest warning and forecasts.
Also expected Thursday are strong winds. A wind advisory will be in effect from 5 a.m. Thursday through 8 p.m. in the San Gabriel Mountains and the Antelope Valley. Forecasters said these areas would be swept by 20 to 30-mile- per-hour winds accompanied by gusts of 45 to 55 mph.
“These winds will peak around noon Thursday and then subside Thursday evening,” a statement said. “When driving, use extra caution. Be prepared for sudden gusty cross winds.”
Officials Wednesday had advised people who reside in the areas affected by the La Tuna Canyon, Creek and Skirball fires to prepare for evacuations and street closures, but late in the afternoon, evacuation orders that had been scheduled to take effect at 6 p.m. in the Kagel Canyon, Lopez Canyon and Little Tujunga Canyon areas were canceled due to an updated forecast.
Mandatory evacuations did go into effect at 6 p.m. Wednesday for La Tuna Canyon Road from the 8300 to the 9000 blocks and the road was closed from the 8300 block to the Foothill (210) Freeway, authorities said.
Voluntary evacuations went into effect for the stretch of La Tuna Canyon Road from the 9000 block to Sunland Boulevard and in an area bordered by Day Street to the north, Plainview Avenue to the east and Sherman Grove Avenue to the west.
All areas are being closely monitored by officials, Los Angeles City Councilwoman Monica Rodriguez said at late morning news conference Wednesday.
The storm — a Pacific weather system greatly beefed up by a subtropical atmospheric river — was forecast to produce 1 to 3 inches of rain in Los Angeles County coastal and valley areas and between 2 and 5 inches in the mountains.
Duarte went into a “yellow alert” status at noon Wednesday for areas below the 2016 Fish Fire burn area. The alert calls for residents to move vehicles, trash bins and other large items out of streets to keep them clear for emergency crews and prevent items from being washed away.
The city also planned to close Mel Canyon Road to through-traffic below the burn area beginning at 6 p.m. but the closure was postponed until Thursday, according to the watch commander at the Los Angeles County Sheriff’s Department’s Temple Station.
Duarte officials were distributing filled sandbags to residents at the corner of Brookridge Road and Opal Canyon Wednesday.
An evacuation shelter was open at the Sylmar Recreation Center, 13109 Borden Ave. and the Sun Valley Recreation Center, 8133 Vineland Avenue.
A shelter at the Westwood Recreation Center at 1350 Sepulveda Blvd. was available for residents who choose to evacuate from the Skirball Fire burn area.
Large animals may be taken to a temporary animal shelter at the Equestrian Park at the Hansen Dam, 11127 Orcas Ave Lake View Terrace. The number is (818) 896-6514.
Dogs, cats and small pets can be taken to the Sylmar Recreation Center at 13109 Borden Ave. in Sylmar or the Los Angeles County Animal Care Center at 31044 Charlie Canyon Road in Castaic.
Residents can call a Joint Information Center at (323) 957-4594 for around the clock updated information on evacuations.
The city of Burbank, meanwhile, postponed until 6 a.m. Thursday a voluntary evacuation order that was to take effect at 8 p.m. Wednesday Once in effect, the order was expected to last through 6 p.m. Thursday for the following streets in danger of flooding and mud flows due to the recent La Tuna Fire:
— Country Club Drive east of Via Montana;
— all of Hamline Place; and
— Groton Drive east of Kenneth.
An evacuation center was established at Verdugo Recreation Center at 3201 W. Verdugo Ave. The center will not accommodate animals.
No-parking restrictions were in effect on:
— Country Club Drive east of Via Montana;
— all of Hamline Place; and
— Groton Drive east of Kenneth.
All of Burbank’s hiking trails have been closed, along with the Stough Canyon Nature Center and Wildwood Canyon recreation area, until further notice.
Temperatures Thursday will mostly range from the low to mid 60s.
The NWS forecast highs in L-A County Thursday of 51 degrees on Mount Wilson; 60 in Saugus; 61 in Palmdale and Lancaster; 62 in Avalon, Burbank, Pasadena and Woodland Hills; 63 in San Gabriel and at LAX; and 64 in Downtown L.A. and Long Beach. Temperatures will remain about the same through Monday, then rise a few degrees Tuesday and a few more Wednesday. No rain is in L.A. County’s forecast beyond Thursday.
In Orange County, the NWS forecast highs of 64 in Newport Beach and San Clemente; 65 in Yorba Linda; 66 in Laguna Beach, Fullerton, Anaheim and Mission Viejo; and 67 in Irvine. Temperatures will begin straying into the 70s in some O.C. communities on Tuesday.
—City News Service