(CNN) More than 10 million people in at least nine western states are under a winter watch, including cities like Seattle and Salt Lake City, as a winter storm sweeps through the region.
The storm will bring up to 30 inches of snow to the drought-stricken Sierras, but will make travel “difficult or impossible.”
“Back-to-back winter storms will bring periods of very difficult to impossible travel over the Sierra passes through Sunday,” the National Weather Service (NWS) office in Reno said.
The snow and rain should begin to taper off for most areas on Friday before the next storm system moves in late Saturday/early Sunday.
Snow rates could reach 2 to 3 inches per hour Thursday and early Friday. This, combined with high winds, can lead to near zero visibility conditions.
The beginning of the winter season
“Today is the first day of meteorological winter, and it feels like it in the Pacific Northwest,” the NWS Portland office said.
While nearly 1 meter of snow could fall in California, in the Rockies expect 12 to 24 inches of widespread snow in places like Montana, Utah and the Colorado mountains. Heavy rainfall along the coast can exceed 100 mm.
A mix of rain and snow is expected for cities like Seattle and Portland. While this will limit the amount of snow that accumulates on the ground, it will still cause travel problems thanks to muddy roads, and sub-zero temperatures will create patches of black ice.
For the city of Seattle, only 1 to 2 inches of snow is expected through Saturday, with a winter weather advisory through Friday night. That would be significant snow and quite rare for Seattle, a city that gets as much annual snow (9 cm) as Little Rock, Arkansas. In fact, Seattle may record more than half of its annual snowfall from this early winter storm.
A winter weather advisory has also been issued for Billings and Missoula, Montana, where snowfall amounts between 2.5 to 7 cm and 7 to 15 cm are forecast, respectively.
For Reno, Nevada, height is everything. In the city itself and along the slopes, 2.4 to 10 cm is expected, but once you exceed 5,000 feet in elevation, the forecast becomes 7 to 17 cm.
Salt Lake City will also pick up a few inches of snow in the city, where 2 to 4 inches are forecast. However, in the mountains, including Park City, totals will be closer to 12 inches.
In Aspen, Colorado, which is also under an avalanche watch Saturday morning, skiers can expect 5 to 10 inches.
Back-to-back winter storms will bring periods of very difficult to impossible travel over Sierra passes through Sunday. See our Winter Storm Warnings for additional information: https://t.co/Hlck0YYqz8. Check with Caltrans for updated road information: https://t.co/rYQgfWT4N2. #cawx pic.twitter.com/E2egHY3G8Q — NWS Reno (@NWSReno) November 30, 2022
The heaviest amounts of snow will fall along the Sierra Range, where 20 to 30 inches are forecast at places like Mammoth Mountain and Mount Shasta.
That’s why the NWS Reno office is urging people to avoid all non-essential travel during high impact periods.
A quick start to the snow season, with a long way to go
While it can cause a lot of displacement problems, all that snow is good for one thing: helping with the drought. But one snowstorm doesn’t mean the whole season will be the same.
Last year, California had its wettest start to the year in more than 40 years. However, precipitation quickly leveled off and the season’s snow cover was only 35% of what would normally be expected.
The fight against drought in California has a new tool: the limiter
Regarding snowpack conditions in the region at this time, the Natural Resources Conservation Service SNOTEL network is currently reporting the following snow water equivalent percentages for the region in the most recent update (November 29):
Pacific Northwest 134% California 135% Great Basin 157% Lower Colorado 152% Upper Colorado 98%
While these numbers are off to a good start, they must continue to have a major impact on the drought conditions, and in turn the water supply, that have plagued the West for decades.
CNN’s Rob Shackelford contributed to this report.
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