Santa Ana winds blew across parts of the Southland again Tuesday, but as the gusts began to subside a storm system began encroaching on the area, setting the stage for a wet Rose Parade and prompting evacuation warnings for residents near recent burn zones.
Wind advisories issued by the National Weather Service that were initially expected to expire Monday night were instead extended until 3 p.m. Tuesday for areas including the Santa Clarita and San Fernando valleys, Malibu, Calabasas and Santa Monica and San Gabriel Mountains.
A storm system will move into the area from the south Wednesday with periods of rain through at least Saturday, heaviest Wednesday night into New Year’s Day, virtually guaranteeing a soggy Rose Parade and New Year’s Day celebrations.
“Light rain will gradually increase across the area (Tuesday night) and Wednesday,” according to the National Weather Service. “The peak of the rainfall in the short term will be Wednesday night through Thursday afternoon with a lingering shower threat Thursday night and Friday.
“Totals through New Year’s Day will generally range from 0.75 to 2.50 inches across coastal and valley areas with 2.00-5.50 inches across the foothills and mountains. An additional 0.10-0.50 is likely on Friday with the lingering shower threat.”
Rainfall rates are expected to remain relative low, in the quarter- to half-inch per hour range, but localized thunderstorms could push that rate as high as one inch per hour, forecasters said.
Given last week’s storms that saturated the ground in many areas, authorities again warned of possible mud and debris flows from the upcoming rain. The National Weather Service issued flood watches covering much of Los Angeles County and Orange County coastal and inland areas for Wednesday evening through Thursday evening.
Gov. Gavin Newsom announced Tuesday that he has directed the California Governor’s Office of Emergency Services to pre-position fire and rescue personnel and resources in areas most at risk for flooding, mud, and debris flows — including parts of Southern California, with a particular eye towards burn scar areas.
Evacuation warnings will take effect at 11 a.m. Wednesday for residents living near recent burn zones across Los Angeles County, including the Palisades, Eaton, Agua Dulce, Franklin, Bridge, Kenneth and Canyon fires, due to the possibility of mud or debris flows.
Caltrans will fully close the 3.6-mile stretch of Topanga Canyon Boulevard between Pacific Coast Highway and Grand View Drive in the unincorporated community of Topanga at 5 p.m. Wednesday in advance of predicted rainstorms and potential debris flows.
The closure follows last week’s Christmas storms that brought mud and debris flows onto Topanga Canyon Boulevard and minor damage onto Pacific Coast Highway.
Caltrans officials are concerned about more damages amid already-saturated slopes on both streets.
The Palisades Fire recovery work zone on Pacific Coast Highway from Sunset Boulevard to Carbon Beach Terrace will remain open, with crews on standby to respond to flooding and debris flows.
Rainfall totals are estimated at up to 3.75 inches in the Palisades Fire burn scar area, with local rain rates of 0.25 up to 1 inch per hour, according to NWS. There is potential for mud and debris flows and isolated flash flooding, according to Caltrans.
Crews are preparing for the storm by moving equipment, placing k-rail and sandbags and stabilizing current retaining wall and other project work on Topanga Canyon Boulevard and PCH.
The county Board of Supervisors scheduled a special meeting for 9:30 a.m. Wednesday to ratify a local emergency proclamation issued earlier by board Chair Hilda Solis. The proclamation allows the county “to seek reimbursement for storm-related damages and accelerate recovery efforts” and ensure that “resources and assistance can be deployed quickly to support residents and communities affected by the storms.”
Forecasters said there is “a near 100% chance” of rain falling on the Rose Parade — and on people camping out for the parade on Wednesday night. Rain has not fallen on the Rose Parade 2006. The floral procession has traditionally managed to avoid precipitation, with rain dampening the event less than a dozen times in its previous 136 years.