(CNN) — More than 10 million people in at least nine western states are under winter surveillance, including cities like Seattle and Salt Lake City, as a winter storm rolls over the region.
The storm will bring up to 30 inches of snow to the drought-stricken Sierras, but will make travel “difficult or impossible.”
“Consecutive winter storms will bring very difficult or impossible travel periods over the Sierra passes through Sunday,” said the National Weather Service (NWS) office in Reno..
The snow and rain are expected to begin to subside on Friday for most areas before the next storm system enters late Saturday or early Sunday.
Snow rates could reach 2 to 3 inches per hour on Thursday and early Friday. This, combined with strong winds, could lead to near-zero visibility conditions.
The beginning of the winter season
“Today is the first day of meteorological winter, and it looks like it’s in the Pacific Northwest,” the NWS Portland office said.
While nearly 3 feet of snow could fall in California, 12 to 24 inches of snowfall is expected in the Rocky Mountains in places like Montana, Utah and the Colorado mountains. Heavy rainfall along the coast could exceed 100 mm.
Cities like Seattle and Portland are forecast for a mix of rain and snow. 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. This would be significant and fairly infrequent snow for Seattle, a city that receives the same amount of average snow per year (3.5 inches) as Little Rock, Arkansas. In fact, Seattle could see more than half of its annual snowfall from this winter storm.
A winter weather advisory has also been issued for Billings and Missoula, Montana, where snowfall is expected to be 1 to 2.5 inches and 2.5 to 6 inches, respectively.
For Reno, Nevada, elevation is everything. In the city itself and along the runways, 2.4 to 10 cm is expected, but once you pass 5,000 feet, the forecast becomes 7 to 17 cm.
Salt Lake City will also experience a few inches of snow in the city, where 2 to 4 inches is expected. However, in the mountains, including Park City, the totals will be closer to 12 inches.
In Aspen, Colorado, also under avalanche surveillance through Saturday morning, skiers can expect 5 to 10 inches.
Back-to-back winter storms will bring periods of very difficult or impossible travel over the Sierra passes through Sunday. See our winter storm advisories for more information: https://t.co/Hlck0YYqz8. Check with Caltrans for up-to-date road information: https://t.co/rYQgfWT4N2. #cawx pic.twitter.com/E2egHY3G8Q
— NWS Reno (@NWSReno) November 30, 2022
The greatest amounts of snow will fall along the Sierra range, where 20 to 30 inches are expected in places like Mammoth Mountain and Mount Shasta.
That’s why the NWS Reno office is urging people to avoid all nonessential travel during high-impact times.
A quick start to the snow season, with a long way to go
While it could cause a lot of moving problems, all that snow is for one thing: to help with the drought. But one blizzard doesn’t mean the entire season will be the same.
Last year, California had the start of its wettest year in more than 40 years. However, the rainfall quickly leveled off and the season’s snow cover was only 35% of what is usually expected.
In regards to snowpack conditions in the region at this time, the Natural Resources Conservation Service’s SNOTEL network is currently reporting the following snowwater percentages to the region in its most recent update (November 29):
Pacific Northwest 134%
California 135%
Big Basin 157%
Lower Colorado 152%
Upper Colorado 98%
While these numbers are off to a strong start, they need to stay that way to have a major impact on drought conditions and, in turn, water supplies, which have plagued the West for decades.
Rob Shackelford of CNN contributed to this report.
