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Storm Updates: Overnight Rain Drenches Southern California With More on the Way

A cold winter storm will bring rain and possibly historic snowfall into the weekend. Here's what to expect and when.

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What to Know

  • Widespread rain and snow are in the forecast into Saturday.
  • A blizzard warning is in effect for LA, Ventura and San Bernardino county mountains.
  • Two to 5 feet of snow are possible by Saturday.

A powerful winter storm will delivered widespread heavy rain and potentially historic snowfall as it moved through Southern California.

Severe weather alerts, including the region's first blizzard warning in decades and a flash flood warning for Los Angeles County, were issued as the cold storm fueled by an atmospheric river over the Pacific unleashed a torrent of moisture. The blizzard warning, indicating snow or blowing snow, reduced visibility and sustained winds of 35 mph or greater, will be in effect for Los Angeles, Ventura and San Bernardino county mountains Friday morning through Saturday afternoon.

Several mountain roads, including the 5 Freeway in northern Los Angeles County, were closed due to snow, ice and poor visibility.

Other areas face flood watches, wind advisories and high surf advisories.

Fallen trees were reported in areas like Santa Barbara and Valley Village where many cars were damaged.

Over 9,000 of Southern California Edison customers in LA County were also affected by power outages during the storm.

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Here's what to expect from the late-February storm.

Friday: Blizzard Warning, Flash Flooding, Widespread Evening Rain

The brunt of the storm will pummel Southern California into Saturday with the most severe conditions arriving late Friday.

A flash flood warning was in effect for parts of Los Angeles County until 5 a.m. Saturday, according to the National Weather Service.

Between 1 and 3 inches of rain were reported in parts of LA County under the warning with additional rainfall amounts of 2 to 5 inches possible.

LA County locations in the warning area include widespread parts of the San Fernando Valley, Griffith Park, downtown LA, Beverly Hills, Alhambra, Santa Clarita, Whittier, West Covina and other parts of the San Gabriel Valley. The warning includes all recent burns scars.

In Los Angeles County, the heaviest rain is expected around 11 p.m. and into the overnight.

A blizzard warning went into effect at 4 a.m. and will continue until 4 p.m. Saturday for LA and Ventura county mountains. Snow totals are expected to reach up to 5 feet at elevations above 4,000 feet by Saturday night.

Areas under the blizzard warning include, Mount Wilson, the Grapevine section of the 5 Freeway, Acton, Mount Pinos and Frazier Park. Travel is highly discouraged in Southern California's mountains.

The 5 Freeway was closed through the Tejon Pass early Friday due to snow and ice. State Route 18 was closed in both directions from its split with Highway 330 in Running Springs to Big Bear Dam due to snow drift and stuck vehicles.

"This is the second time we've seen a blizzard warning in over 30 years," said NBC4 forecaster Belen De Leon. "So we're going to see excessive snow in the mountains and gusts up to 75 mph, plus reduced visibility."

Weather officials are warning blizzard conditions along with snow, strong winds and low visibility would make it very difficult to drive through the San Bernardino County mountains.

The blizzard warning does not include the Santa Monica Mountains.

The blizzard warning was extended Thursday to include the San Bernardino County mountains. Communities in the warning area area Wrightwood, Big Bear, Lake Arrowhead, Crestline and Running Springs.

The NWS San Diego office said the blizzard warning is the first issued by the office.

"Travel will be VERY DIFFICULT TO IMPOSSIBLE due to the extremely heavy snow and extremely high winds expected," the agency tweeted.

"You don't want to be on the road (Friday)," said De Leon.

Saturday: Rain, Snow Through the Morning

Two to 5 feet of snow are expected above 5,000 feet by Saturday as the storm continues to hammer the region. Some areas could get as much as 7 feet.

Snow accumulations of 6 to 12 inches are possible by Saturday night at elevations as low as 2,000 feet.

Heavy rain will fall overnight in widespread parts of Southern California. By 10 a.m., snow and rain will begin to diminish with showers lingering into Sunday.

"The rain is getting heavier Friday evening through Saturday morning," said De Leon.

Rain and Snow Estimates

Rainfall estimates range from 2 to 5 inches for most areas and 5 to 7 inches in foothill communities.

Snowfall estimates include 2 to 5 feet, and possibly up to 7 feet, above 5,000 feet. Elevations between 3,500 and 4,500 feet will see 6 to 18 inches of snow.  

Rainfall totals as of 10 a.m. Friday included 1.12 inches at the Hollywood Reservoir and in Santa Monica, 1.48 inches in Beverly Hills, 2.62 inches in Woodland Hills, 1.63 inches in Northridge. 1.63 inches in East Pasadena and 1.93 inches in Newhall.

Another storm is on track to arrive Tuesday into Wednesday.

A blizzard warning was issued for LA and Ventura county mountains. Stephanie Olmo reports for the NBC4 News at 4 p.m. on Wednesday Feb. 23, 2023.

What's a Blizzard Warning?

A blizzard warning generally indicates winter weather conditions that include snow, blowing snow, reduced visibility, strong sustained winds. It is a more severe weather warning that a winter storm warning.

Here's how the National Weather Service defines a blizzard warning.

The following conditions are occurring or expected within the next 12 to 18 hours.

  1. Snow and/or blowing snow reducing visibility to 1/4 mile or less for 3 hours or longer
    and
  2. Sustained winds of 35 mph or greater or frequent gusts to 35 mph or greater.

Note that there is no temperature requirement that must be met for blizzard conditions.

SoCal Weather Photos: Scenes From the Late-February Winter Storm

A less severe winter storm warning is issued when a combination of hazardous winter weather is occurring or imminent.

Significant and hazardous winter weather is defined by the National Weather Service as a combination of the following.

  1. Five inches or more of snow/sleet within a 12-hour period or 7 inches or more of snow/sleet within a 24-hour period
    and/or
  2. Enough ice accumulation to cause damage to trees or powerlines
    and/or
  3. A life threatening or damaging combination of snow and/or ice accumulation with wind.

California Drought Update

The most severe drought conditions that plagued California at the start of the water year in October were wiped out by January's storms, which also were fueled by atmospheric rivers.

In the most recent U.S. Drought Monitor report released Thursday, 33 percent of California was in severe drought, the weekly Monitor's third most severe category. At the start of the water year, 94 percent of the state was in severe drought.

Eighty-five percent of the state remains in moderate drought, the report's least severe category. That figure was at 99.76 percent at the start of the water year.

California has spent most of the last 15 years in drought conditions. The current three-year dry spell included one of the driest late winters on record. 

The state's normal wet season runs from late fall to the end of winter, but dismal precipitation left about 95 percent of California in severe drought at the start of spring. By September, nearly all of California was in drought.

Much of California’s water comes from melting snow in the Sierra Nevada Mountains. In an ideal scenario, storms blanket the mountains with snow during winter, building up the natural reservoir. That snow then melts in late spring and early summer, replenishing the state's water system. Snowpack was far below normal in Spring 2022, but rebounded during January's storms.

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