Blockbuster storm, intense atmospheric river blast California
By
Alex Sosnowski, AccuWeather senior meteorologist
Updated Jan 28, 2021 7:06 PM EST
An intense storm began walloping California on Tuesday, triggering several inches of rain, more than 2 feet of snow and gusts topping 100 mph. The system will continue to blast California and the drought in the region, but it will raise concerns for dangerous flash flooding and mudslides into the end of the week.
The blockbuster storm was being fueled by an atmospheric river, one that Extreme Meteorologist Reed Timmer described as "on steroids" to emphasize the intensity of the event. On top of tapping into copious amounts of moisture from deep in the Pacific Ocean, the storm will move very slowly, inching southeastward along the California coast. The storm's slow movement will contribute to excessive precipitation amounts.
This radar image, captured on Thursday morning, Jan. 28, 2021, shows an atmospheric river blasting areas from the Central Coast of California to the northern Sierra Nevada. Rain is depicted in green, yellow and red while snow is shown in blue. (AccuWeather)
Locally strong winds will also continue to pound the region into Friday, leading to other issues. More than 350,000 utility customers were without power in California early Wednesday, according to PowerOutage.us.
However, the peak wind gusts have already occurred during the storm. By early Thursday morning, the number of power outages had fallen to just over 130,000 customers. A few gusts between 40 and 60 mph can occur in parts of Southern California and Nevada into Thursday night.
Winds are not expected to raise the fire risk due to rain and snow accompanying the system, strong enough gusts will continue to lead to sporadic and regional power outages. Gusty crosswinds can add to the difficult driving conditions caused by the rain and snow.
Blizzard warnings were in effect for part of the Sierra Nevada, where the heavy snow will be accompanied by wind gusts greater than 70 mph. People in Lake Tahoe and Mammoth Lakes should brace for the potential for long-lasting blizzard conditions.
The storm is far from over, and in much of Southern California, the worst of the storm is yet to come. Rain, snow and wind from the storm are forecast to continue across the state into Friday.
Meteorologists have been sounding the alarm that the potent storm will bring extreme impacts, with an AccuWeather StormMax™ of 10 feet of snow and 20 inches of rain expected. Peak winds will continue to top hurricane force (74 mph or greater).
The combination of strong winds and snow produced blizzard conditions in portions of the Siskyou Mountains and the Sierra Nevada on Wednesday. The high country of these mountain ranges will likely pick up amounts ranging from 3-6 feet of snow into Friday. Snow will come down at varying intensity throughout the event, and periodic blizzard conditions are likely to lead to road closures into the end of the week.
"With so much snow on the way in a relatively short period of time, the risk of avalanches will increase greatly in the Sierra," AccuWeather Senior Meteorologist Adam Douty said.
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In Southern California, snow levels are expected to be higher with the storm from Wednesday to Friday, which should keep most of the accumulating snow above pass levels. "The most likely time for enough snow to make roads slippery over the Grapevine will be from Thursday night to early Friday," stated AccuWeather Senior Meteorologist Dave Houk.
Snow can still be heavy across the highest elevations of Southern California throughout the storm, adding even more to the snowpack at some mountain resorts in the region.
Torrential rainfall across the lower and intermediate elevations in the region will mostly be beneficial in some areas, but heavier amounts will lead to problems and could cause life-threatening flash flooding and mudslides in other communities.
Prior to the train of storms that began during the middle of January, the region faced abnormally dry to exceptional drought conditions.
There is no question the storm will ease drought conditions in the region, and there is the likelihood this single storm can nearly wipe out drought in some areas, according to AccuWeather forecasters. Additionally, the deep load of snow over the high country will provide ample runoff during the warm season. However, enough rain could fall from the storm to push streams and rivers to bank full in some cases.
A general 3-6 inches of rain is forecast over California outside of the deserts, which will still receive a thorough soaking. However, the west- and southwest-facing lower slopes of the Coast Ranges and Sierra Nevada are likely to receive 6-12 inches of rain with locally higher amounts.
Chalk Peak in the coast ranges northwest of Santa Cruz, California, a coastal town to the south of San Francisco, had picked up 8.16 inches of rain since Tuesday.
Recent burn scars, which are void of the vegetation that helps to hold back runoff, will be most prone to flash flooding and mudslides during the storm.
Forecasters say some of the areas of greatest concern are with the burn scars associated with the SCU Lightning Complex and Creek Fire in Central California, August and North Complexes in Northern California and the Bobcat Fire in Southern California.
"The firehose of rain, or the atmospheric river, is likely to crawl through the Central Coast region of California through Thursday evening," Douty said. "This area has had some recent fires and may pick up some of the heaviest rainfall from the storm."
"The storm itself will 'wobble' at times as it spins just off the coast. This will cause a plume of the greatest moisture to shift at times, shifting where the heaviest rain and snow are directed through the week," Douty said.
The worst of the rain and the greatest risk of flash flooding in the Los Angeles and San Diego areas are forecast to occur from late Thursday afternoon into Thursday night. Motorists should be prepared for high water on some roads, as well as rocks and other debris in hilly areas.
During Friday, thunderstorms with locally gusty winds and small hail can erupt over parts of Southern California. A couple of the storms could produce a waterspout or brief tornado.
In the wake of the storm, runoff will continue into area streams and rivers through this weekend. The risk of mudslides and avalanches is expected to continue even after the last raindrops and snowflakes fall.
The next storm currently lurking over the Pacific will largely set its sights on the Northwest and Northern California from this weekend to early next week, but the entire Southwest will face chances for active weather through the first part of February.
"The storms will keep coming in the Southwest," said AccuWeather Lead Long-Range Meteorologist Paul Pastelok. "More snow and rain will fall across the Southwest, leading to some flooding and slippery travel in the higher elevations into the first days of February."
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier and Verizon Fios.
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News / Winter Weather
Blockbuster storm, intense atmospheric river blast California
By Alex Sosnowski, AccuWeather senior meteorologist
Updated Jan 28, 2021 7:06 PM EST
An intense storm began walloping California on Tuesday, triggering several inches of rain, more than 2 feet of snow and gusts topping 100 mph. The system will continue to blast California and the drought in the region, but it will raise concerns for dangerous flash flooding and mudslides into the end of the week.
The blockbuster storm was being fueled by an atmospheric river, one that Extreme Meteorologist Reed Timmer described as "on steroids" to emphasize the intensity of the event. On top of tapping into copious amounts of moisture from deep in the Pacific Ocean, the storm will move very slowly, inching southeastward along the California coast. The storm's slow movement will contribute to excessive precipitation amounts.
This radar image, captured on Thursday morning, Jan. 28, 2021, shows an atmospheric river blasting areas from the Central Coast of California to the northern Sierra Nevada. Rain is depicted in green, yellow and red while snow is shown in blue. (AccuWeather)
Locally strong winds will also continue to pound the region into Friday, leading to other issues. More than 350,000 utility customers were without power in California early Wednesday, according to PowerOutage.us.
However, the peak wind gusts have already occurred during the storm. By early Thursday morning, the number of power outages had fallen to just over 130,000 customers. A few gusts between 40 and 60 mph can occur in parts of Southern California and Nevada into Thursday night.
Winds are not expected to raise the fire risk due to rain and snow accompanying the system, strong enough gusts will continue to lead to sporadic and regional power outages. Gusty crosswinds can add to the difficult driving conditions caused by the rain and snow.
Blizzard warnings were in effect for part of the Sierra Nevada, where the heavy snow will be accompanied by wind gusts greater than 70 mph. People in Lake Tahoe and Mammoth Lakes should brace for the potential for long-lasting blizzard conditions.
The storm is far from over, and in much of Southern California, the worst of the storm is yet to come. Rain, snow and wind from the storm are forecast to continue across the state into Friday.
Meteorologists have been sounding the alarm that the potent storm will bring extreme impacts, with an AccuWeather StormMax™ of 10 feet of snow and 20 inches of rain expected. Peak winds will continue to top hurricane force (74 mph or greater).
The combination of strong winds and snow produced blizzard conditions in portions of the Siskyou Mountains and the Sierra Nevada on Wednesday. The high country of these mountain ranges will likely pick up amounts ranging from 3-6 feet of snow into Friday. Snow will come down at varying intensity throughout the event, and periodic blizzard conditions are likely to lead to road closures into the end of the week.
"With so much snow on the way in a relatively short period of time, the risk of avalanches will increase greatly in the Sierra," AccuWeather Senior Meteorologist Adam Douty said.
CLICK HERE FOR THE FREE ACCUWEATHER APP
In Southern California, snow levels are expected to be higher with the storm from Wednesday to Friday, which should keep most of the accumulating snow above pass levels. "The most likely time for enough snow to make roads slippery over the Grapevine will be from Thursday night to early Friday," stated AccuWeather Senior Meteorologist Dave Houk.
Snow can still be heavy across the highest elevations of Southern California throughout the storm, adding even more to the snowpack at some mountain resorts in the region.
Torrential rainfall across the lower and intermediate elevations in the region will mostly be beneficial in some areas, but heavier amounts will lead to problems and could cause life-threatening flash flooding and mudslides in other communities.
Prior to the train of storms that began during the middle of January, the region faced abnormally dry to exceptional drought conditions.
The current U.S. Drought Monitor map for California. (U.S. Drought Monitor)
There is no question the storm will ease drought conditions in the region, and there is the likelihood this single storm can nearly wipe out drought in some areas, according to AccuWeather forecasters. Additionally, the deep load of snow over the high country will provide ample runoff during the warm season. However, enough rain could fall from the storm to push streams and rivers to bank full in some cases.
A general 3-6 inches of rain is forecast over California outside of the deserts, which will still receive a thorough soaking. However, the west- and southwest-facing lower slopes of the Coast Ranges and Sierra Nevada are likely to receive 6-12 inches of rain with locally higher amounts.
Chalk Peak in the coast ranges northwest of Santa Cruz, California, a coastal town to the south of San Francisco, had picked up 8.16 inches of rain since Tuesday.
Recent burn scars, which are void of the vegetation that helps to hold back runoff, will be most prone to flash flooding and mudslides during the storm.
Forecasters say some of the areas of greatest concern are with the burn scars associated with the SCU Lightning Complex and Creek Fire in Central California, August and North Complexes in Northern California and the Bobcat Fire in Southern California.
"The firehose of rain, or the atmospheric river, is likely to crawl through the Central Coast region of California through Thursday evening," Douty said. "This area has had some recent fires and may pick up some of the heaviest rainfall from the storm."
"The storm itself will 'wobble' at times as it spins just off the coast. This will cause a plume of the greatest moisture to shift at times, shifting where the heaviest rain and snow are directed through the week," Douty said.
The worst of the rain and the greatest risk of flash flooding in the Los Angeles and San Diego areas are forecast to occur from late Thursday afternoon into Thursday night. Motorists should be prepared for high water on some roads, as well as rocks and other debris in hilly areas.
During Friday, thunderstorms with locally gusty winds and small hail can erupt over parts of Southern California. A couple of the storms could produce a waterspout or brief tornado.
In the wake of the storm, runoff will continue into area streams and rivers through this weekend. The risk of mudslides and avalanches is expected to continue even after the last raindrops and snowflakes fall.
The next storm currently lurking over the Pacific will largely set its sights on the Northwest and Northern California from this weekend to early next week, but the entire Southwest will face chances for active weather through the first part of February.
Related:
"The storms will keep coming in the Southwest," said AccuWeather Lead Long-Range Meteorologist Paul Pastelok. "More snow and rain will fall across the Southwest, leading to some flooding and slippery travel in the higher elevations into the first days of February."
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier and Verizon Fios.
Report a Typo