Late-week storm to slam California with flooding, mountain snow and wind

By Alex Sosnowski, AccuWeather senior meteorologist

April 4,2017, 10:39:00AM,EDT

 

 

A powerful storm packing heavy rain, snow and strong winds will slam California, Oregon and Washington late this week and into this weekend.
Impacts from the storm could approach some of the biggest storms of this past winter for the region in terms of potential flooding and damaging winds from central and Northern California to western Oregon.
The heavy rain and strong winds will impact a portion of the Interstate 5 corridor.

"Winds can top 60 mph along the coasts, over the ridges and through the passes," according to AccuWeather Senior Meteorologist Brett Anderson.
"Gusts this strong can topple trees, trigger power outages and flip trucks over."
In addition to urban flooding, the combination of heavy rain and melting snow at intermediate elevations will raise the risk of small stream and short-run river flooding. Major rivers and reservoirs will experience another surge of water.
Rainfall from the storm will average 3-6 inches along the west-facing slopes of the Coast Ranges, the Olympics and the lower elevations of the Cascades and Sierra Nevada. However, locally higher amounts topping 8 inches are possible.
From 1 to 2 inches of rain will fall over the Sacramento and upper San Joaquin valleys of California.
Motorists and airline passengers should anticipate delays in San Francisco and Sacramento, California, from Thursday evening through Friday.
The rain can be intense enough to trigger mudslides, especially in recent wildfire areas.
Farther north, in Seattle and Portland, Oregon, the rainfall will be less intense but can lead to minor travel delays late this week and this weekend.
Enough rain can still fall to cause slick conditions for a time around Los Angeles and San Diego from late Friday to early Saturday. Locally gusty winds will follow the rain in parts of Southern California this weekend.
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Periods of snow and rain will occur over the passes of the Sierra Nevada and Cascades late this week. However, snow levels will lower as the storm progresses into the weekend.
Enough snow is forecast to fall over Donner Pass along I-80 in California to make for wintry travel and slippery conditions. The pass could close for a time, due to the combination of heavy snow and strong wind.
Farther north, slushy conditions can develop over Snoqualmie Pass along I-90 in Washington for a time this weekend.
The high country of the Sierra Nevada and Cascades will receive 1-2 feet of snow from the storm into this weekend. Hikers should avoid the high country due to the risk of becoming stranded from the storm's heavy snow and wind.
The storm will add to the already well above-average snowfall for the season in the high country.