California braces for massive storm; evacuation warnings, closures in LA

Light rain began to fall in California Wednesday afternoon as the state braced for the arrival of a major Pacific storm by enacting road closures and issuing evacuation warnings in parts of Los Angeles and Malibu vulnerable to mudslides and debris flows.

"The main show is still tonight," the National Weather Service in Los Angeles said in a midday forecast update. "A fast- moving cold front will blast through the area overnight with most of the steady rain finished by 8 a.m. PDT Thursday, if not sooner."

The potent storm will put nearly the entire central U.S. at risk of dangerous weather later this week, including what could be "the most significant severe weather outbreak of the year" so far, AccuWeather said. But first, the storm will dump several feet of snow along the Sierra Nevada and bring torrential rain to San Francisco, Los Angeles and San Diego. A smaller storm system moved over the state on Tuesday.

The incoming rain could fall at rates of an inch per hour, raising the risk of flooding, mudslides and debris flows, especially in areas charred by the wildfires that engulfed whole neighborhoods earlier this year.

The Los Angeles Fire Department issued evacuation warnings and orders for residents in the areas torched by the Palisades, Sunset and Hurst wildfires. Over two dozen neighborhoods in Malibu were also placed under evacuation warnings.

"Residents should prepare to evacuate now due to the significant risk of flash flooding, debris flows and mudslides," the city's office of public safety said in a statement on social media. "These hazards pose a serious threat to life and property."

In addition to the evacuation advisories, officials shut down several major roads, including a section of Pacific Coast Highway in Malibu, Las Flores Canyon Road and Malibu Canyon Road.

Water quality advisories issued for all LA county beaches

The Los Angeles County Department of Health issued an advisory telling beachgoers to stay out of the water "due to potentially higher bacteria levels."

The county said heavy rain from the incoming storm could carry bacteria, chemicals, debris and other hazards into public waterways.

"Individuals who enter the water in these areas could become ill," the health department said, adding that areas near storm drains, creeks and rivers are at most risk.

The ocean water quality advisory will be in effect until at least 4 p.m. Friday, the agency said.

Multiple feet of snow to blanket the Sierra Nevada

The National Weather Service anticipates between 1 to 3 feet of snow piling up across the Sierra Nevada this week, raising the risk of avalanches and making travel at high elevations dangerous.

"Heavy snow and powerful wind gusts of 40-70 mph below many major passes will create dangerous to potentially impossible travel conditions across the Sierra Nevada and northern California higher terrain this afternoon into Thursday," the National Weather Service said.

AccuWeather warned blizzard conditions are possible in the Sierra Nevada due to the high winds. The storm heading east this week may bring blizzard conditions to the high Plains.

Fire danger in the Plains

While California deals with rain and snow, persistent dry, warm and windy conditions will promote critical fire weather conditions across the southern high Plains on Wednesday and through the rest of the week. Red flag warnings are in place in Texas, New Mexico, Colorado, Kansas and Oklahoma, meaning conditions are ripe for wildfires to spread.

The most dangerous conditions Wednesday are expected in western Texas, where the Storm Prediction Center has highlighted an "extreme" risk for wildfires.

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Storms brewing in the South

A low pressure system will move over the southern Plains on Wednesday, possibly bringing severe thunderstorms to northeast Texas, Oklahoma, western Arkansas and Louisiana, where large hail and wind damage is possible into Thursday, the weather service said.

These storms are only a preview of the major impacts forecast for the central U.S. on Friday and into the weekend, when the storm set to wallop California makes its way across the country.

The colossal storm will put over 100 million people at risk of severe weather, from blizzard conditions in the northern Plains to tornadoes and wildfires in the South. It has the potential to be "the most significant severe weather outbreak of the year" so far, AccuWeather said.

This article originally appeared on USA TODAY: Massive storm to pummel California, forces evacuations in LA area