Storm Warning: Fountain Valley Braces For Rain, Wind, Mountain Snow

FOUNTAIN VALLEY, CA — The National Weather Service continues to report on the enormous storm that is barreling through the southland. In Orange County, a flash flood watch will be in force from noon Friday through Saturday afternoon.

The storm will start making itself felt Friday morning and continue through Saturday morning. Up to an inch of rain per hour is expected in some areas in part because the storm has been tapping into a so-called atmospheric river over the Pacific, sucking up volumes of warm subtropical moisture, forecasters said.
Estimates are that the region will receive 2-6 inches of rain in coastal and valley areas and between 5 and 10 inches in the San Gabriel mountains and foothills, they said.

"Strong southerly winds combined with ample moisture will lead to periods of very heavy rain, with rain rates at times of around 1 inch per hour," according to the National Weather Service. The rain is expected to taper off Saturday morning, causing the threat of flash flooding to disappear around noon, although scattered showers are possible through Saturday evening.

Turn Around, Don't Drown

"There will be the threat of flash flooding with mud and debris flows in and around the recent burn areas, especially with Friday's storm," according to the NWS, which said widespread urban roadway flooding is also possible, along with flooding in creeks and small streams, and rock and mudslides, especially near canyon roadways.

High surf is expected along the coast through Sunday as a result of a large storm-generated westerly swell, with the biggest surf expected Saturday. A high surf advisory will be in effect until 7 a.m. Sunday in Los Angeles County and until 10 p.m. Sunday in Orange County, said the NWS, warning of surf of 8 to 13 feet on Saturday.

"Large waves and strong rip currents will increase the risk of ocean drowning for swimmers and surfers," according to the NWS statement. "Large breaking waves can cause injury, wash people off beaches or rocks and capsize small boats near shore."

Also in effect is a small craft advisory that will be in effect until noon Friday and a gale watch -- issued in cases of winds of between 34 and 47 knots -- through late Saturday night. During that period, there could be combined seas of 14 to 17 feet and inexperienced mariners should stay off the water, the NWS said.

Residents are bracing for the storm in Glendora, near the site of the Colby wildfire, where officials issued a yellow alert, also ordering residents to remove vehicles and other obstructions from streets to ensure they are not washed away in a mudflow or obstruct emergency vehicles trying to reach the area.

"A strong storm system tapping into deep subtropical moisture will generate heavy rain," an NWS statement warned, adding that scattered showers and a slight chance of thunderstorms are in Friday evening's forecast. A flash flood watch will be in effect from 7 a.m. through Saturday morning everywhere in Los Angeles County.

In the mountains, between 1 and 2 feet of snow are possible above 8,000 feet and between 6 and 12 inches above 6,000 feet, the NWS said. The snow level will drop to between 5,000 and 5,500 feet late Friday evening and Saturday morning.

At the same time, the mountains will be swept by south-to-southeast winds of between 35 and 50 miles per hour, gusting to 70 mph, according to the NWS. A winter storm warning denoting highly challenging travel conditions characterized by snow, fierce winds, blowing snow and icy roads will be in force in the San Gabriel mountains from 7 a.m. Friday until 11 a.m. Saturday.

"Heavy snow, gusty winds, low visibility in blowing snow, and icy roads make for dangerous driving conditions," according to the NWS. "Only travel in an emergency," an NWS statement said, adding motorists traveling in mountain areas should have emergency supplies, including a flashlight, food and water, and extra clothing and blankets.

A high wind warning signifying winds or gusts of at least 58 mph will be in effect from 7 Friday morning until 7 Friday evening in the Santa Monica Mountain Recreational area and the Santa Clarita Valley, with both areas expected to experience southeast-to-south winds of 30-40 mph and 60-mph gusts. A high wind warning will also be in effect from 9 a.m. to 9 p.m. Friday on Santa Catalina Island, where 35-45 mph winds and 60-mph gusts are forecast, and from this morning until 2 a.m. Saturday in Orange County.

"Winds this strong will likely down trees and power lines, causing property damage or power outages," an NWS statement said.

A less severe wind advisory, signaling winds of at least 35 mph, will be in effect from 7 a.m. to 7 p.m. in the San Fernando and San Gabriel valleys, L.A. County beach cities, metropolitan L.A., the downtown area and the Hollywood Hills, with east-to-southeast winds of 25 to 35 mph expected in those areas, along with 50 mph gusts.

A wind advisory will also be in force, from 10 a.m. to 10 p.m., in the Antelope Valley, where 25-35 south-to-southeast winds of 25-35 mph are expected, along with 55-mph gusts.

Temperatures, meanwhile, will be mostly in the low 60s Friday, slipping a few degrees Saturday.

Friday's rainfall is being generated by the second of back-to-back weather systems, although the first, which showed up late Thursday afternoon, amounted to very little, generating only trace amounts of rain or rainfall measured only in the hundredths of an inch , NWS forecasters said.