Major storm to bring blizzard, feet of snow and flooding rain to Southern California
A large and disruptive storm system tracking south just offshore of the West Coast on Thursday was bringing some impacts to California. As the storm zeroes in on the southern part of the Golden State, it is forecast to ramp up in intensity into Saturday and produce heavy rain, snow and even rare blizzard conditions in the mountains around the Los Angeles area.
AccuWeather meteorologists warn that this storm has the potential to be the most impactful storm of the winter, and perhaps in a number of years, for Southern California due to the risks of flooding, snow in low elevations and widespread travel disruptions.
Snow fell close to sea level along the coast of Northern California on Thursday morning and more rain and snow were seen on radar across a larger portion of the state on Friday. During Wednesday afternoon and evening, as the storm was spinning just off the coast of Oregon, heavy snow buried roads in the Portland area and left numerous motorists stranded.
Already some of the major passes have been shut down by the sprawling winter storm on Friday morning. Portions of Interstate 5 over the higher terrain in Northern California were closed, as well as Tejon Pass in Southern California. I-80 over Donner Pass, California, was also closed.
More than a foot of snow was already reported in Northern California, including 18 inches near Lake Spaulding.
As the storm continues its southward push, it will grab more moisture while retaining its cold nature. Even though rain amounts may not be exceptional around the San Francisco Bay Area through Friday night, temperatures will be low enough to allow wet snow to mix in over the hills in the region, and a slushy accumulation can begin at around 1,000 feet in elevation in Central California. There is a risk that enough clinging snow could fall between 1,000 and 2,500 feet to cause tree limbs to break and power lines to come down.
From about Point Conception, California, to areas south is where the storm is likely to really hit its stride as it spins just offshore on Friday night. The strength of the storm combined with subtropical moisture will unleash a tremendous amount of rain as snow falls at very low elevations, according to AccuWeather meteorologists.
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AccuWeather's team of forecasters has been warning about the chances of snow and blizzard conditions since last week. On Wednesday, the National Weather Service office in Los Angeles issued a rare blizzard warning for the mountains to the north and northeast of the city. The NWS office said on Twitter that it was the first blizzard warning in the area since 1989.
This zone includes the Tejon (Interstate 5) and Cajon (I-15) passes. Both are likely to experience highly adverse and dangerous conditions due to excessive snowfall, strong winds and near-zero visibility in blowing snow during the storm. Both locations have the potential to pick up 2 feet of snow or more.
"The higher terrain along I-8 in San Diego County and I-10 over the Inland Empire is also likely to clogged with heavy snow and may close," said Ken Clark, a retired AccuWeather meteorologist and Southern California resident who spent more than four decades forecasting the weather across the western U.S. "This will be an epic storm for much of Southern California," Clark added.
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Heavy, travel-snarling snow will not be limited to areas outlined by National Weather Service blizzard warnings. |
"I've been [living] out here going on 27 years," Clark said. "I've seen snow at low elevations before but the potential [with this storm] is more than I've seen in the years I've been forecasting."
Travel may be shut down due to dangerous conditions and road closures from high water, washouts and debris flows at low elevations and heavy snow in the foothills, mountains and passes, Rayno added. There is a significant risk for some people to be stranded in vehicles or isolated for an extended period in the storm's wake.
"The absolute worst conditions in the zone from Los Angeles to San Diego will be from Friday evening to Saturday morning," AccuWeather Chief On-Air Meteorologist Bernie Rayno said. This is when temperatures will tumble over the region, and snow levels will lower, following a slight warmup from Friday.
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The combination of rain, wind and poor visibility is likely to lead to major airline delays and numerous flight cancellations at the major hubs and regional airports in Central and Southern California. These can have ripple effects on flights across the country as crews and aircraft are displaced.
"Our meteorologists remain highly concerned about the risk of significant tree damage and power outages in the intermediate elevations of 1,000 to 2,000 feet during the storm in Southern California where several inches of snow is likely to fall," AccuWeather Chief Meteorologist Jonathan Porter said. "At this approximate elevation, heavy, wet snow would cling to trees and power lines much more effectively than the fluffier snow expected at higher elevations."
From Friday night to Saturday, a fire hose effect of moisture will be aimed at coastal areas of Southern California. At the storm's peak on Friday night, rainfall rates of 0.50 of an inch to 1 inch per hour will be possible. Up in the mountains, snow may come down at the rate of several inches per hour, resulting in several feet over the highest elevations.
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Widespread rainfall totals of 2-4 inches are foreseen with a zone of 4-8 inches of rain possible in the foothills north of Los Angeles. It's in this part of the region where an AccuWeather Local StormMax™ of 12 inches is most likely.
Along the immediate Southern California coast, the storm was already creating stiff onshore breezes and pounding surf, according to storm chaser and extreme meteorologist Reed Timmer. As the storm drops southward into the weekend, conditions are likely to worsen, with forecasters warning of significant beach erosion and the risk of coastal flooding.
Multiple storms have hit Southern California with heavy rain and heavy mountain snow in recent years. However, this storm is likely to leave a lasting impression for a generation in terms of the impacts from torrential rain, low-elevation snow and the amount of snow that piles up over the mountains.
A couple of additional storms are likely to drop southward along the Pacific coast starting this weekend in the Northwest and reaching portions of California by early next week. While snow levels may not be quite as low as the storm rolling through the region into Saturday, more snow may pile up in the mountains and over some of the hills, while rain soaks the lowest elevations.
Flooding rain and heavy snow will also fall on the northwestern corner of Mexico from the storm, resulting in major travel disruptions.
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There has been a major reversal in the severity of drought conditions in California when compared to the early autumn, according to the United States Drought Monitor.
The end result of the storm at hand and storms in the near future will go a long way toward reducing the remaining drought conditions in California. It is possible in the coming weeks that portions of the state and region may become drought-free for a time.
The rounds of stormy and unsettled conditions may persist in Southern California into mid-March, including around March 12, the day the Academy Awards are held in Los Angeles.
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