The abundance of snow that continues to fall in half a dozen states in the northwestern United States has covered important highways and triggered avalanche warnings that may threaten the return home of those who traveled for Christmas.
In parts of Nevada, Utah, Idaho, Montana, Colorado and California, meteorologists have warned that the visibility of drivers may be compromised.
Weather conditions are expected to continue until the middle of this week, the last of the year.
"Avalanches can travel long distances and can hit lower-angle terrain that is normally considered safe," the Sierra Oriental Avalanche Center warned Sunday.
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A major storm this Christmas weekend caused the closure of essential highways in mountains of northern California and Nevada.
Forecasters have warned that traveling the Sierra Nevada could be difficult for several days, in part
because of slippery conditions and rock slides.
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In Reno, Nevada, authorities reported a 20-car crash on Interstate 395, resulting in three injuries.
Drivers described having difficulty seeing the road.
"Expect long travel delays on all highways," the National Weather Service office in Reno said on Twitter Sunday.
“Today is one of those days to stay home if you can.
More snow is on the way too!
"
The weather service issued a winter storm warning for the Lake Tahoe metropolitan area until 1:00 am Tuesday due to possible "widespread bleaching conditions" and wind gusts that could exceed 45 mph (72 kph).
The turbulent weather has spread from San Diego to Seattle.
More than a foot (0.3 meters) of snow was recorded near Port Angeles on Puget Sound in Washington state.
Snowfall was also reported in the Portland, Oregon area, where "cold Arctic air" moved, according to meteorologists.
At least an inch of snow was reported Sunday in the Seattle and Portland regions
, which generally receive no snow.
Eugene, an Oregon city, declared a snow and ice emergency Sunday morning, urging residents to move their vehicles off emergency routes.
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"The weather is expected to continue to deteriorate throughout the day on Sunday as more snow moves through the area," the city warned.
Los Angeles International Airport said a "storm-related electrical problem" led to the partial closure of Terminal 5, causing passengers returning from their Christmas trips to be diverted to other terminals.
"Cancellations and delays are possible, so it will be important to check the status of your flight today if you are flying through Terminal 5," the airport tweeted.
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The continued storms were well received in parts of California, where the Sierra snow cover had been at
dangerously low levels after weeks of dry weather.
But the state Department of Water Resources reported on Christmas Eve that snow cover was between 114% and 137% of normal and more snow is expected.
During the beginning of the week, heavy rains are expected at lower elevations, possibly causing localized flash floods in places where the soil is saturated.
Las Vegas, for example, has received 2 inches of rain since Wednesday, four times its December average.
Rain is expected to return there on Monday and possibly mix with some snow on Tuesday.
More rain is also forecast for parts of the West Coast that experienced heavy rain in the past 24 hours.
That includes areas of Santa Barbara County, California and other northwestern Los Angeles suburbs, which already accumulate more than an inch of rain.
