As people across the country prepare for holiday travel, dangerous wind gusts and heavy snow will produce hazardous conditions and potential infrastructure impacts from the Northwest to the North-Central U.S., the National Weather Service said Wednesday.
Meanwhile, 8 million people remain under flood watches in swaths of the Northwest on Wednesday, as 31 million people are under strong wind alerts across more than half the country.
"Powerful winds combined with periods of snow across the Northern Plains are likely to produce whiteout conditions tonight into Thursday," the National Weather Service said.
Snow squalls across the Northern High Plains could cause rapid visibility reductions Wednesday night.
"This will cause extremely hazardous travel," the weather service said.
Rounds of heavy snow are also expected in the higher terrains of the Cascades and the Northern Rockies on Wednesday. The weather service said that "additional power outages and tree damage are possible Thursday and Friday due to a combination of heavy, wet snow causing added strain on trees and power lines."
For the 31 million people under wind alerts stretching from the Pacific Northwest across the Rockies and into the Plains and parts of the Midwest, widespread damaging winds could cause numerous power outages and more dangerous travel conditions.
Across Colorado, the strong winds and low relative humidity will lead to a high fire danger, including along the Interstate 25 corridor. Wind gusts of 60 mph to 80 mph, with isolated gusts up to 90 mph in the mountains, will begin early Wednesday afternoon and last into the evening.
Boulder, Colorado, will get peak wind gusts of 80 mph, with Denver potentially reaching 48 mph. Bismarck, North Dakota, is forecast to get peak winds up to 61 mph, and Spokane, Washington, is forecast to get winds of 50 mph. Reno, Nevada, will get peak wind gusts of 43 mph.
Flood watches are in effect for parts of western Washington, Oregon and northern Idaho and Montana on Wednesday.
"Rain at the surface and lower elevations of the Pacific Northwest mountain ranges will intensify over the coming days and exacerbate flooding of rivers, creeks and streams through Friday afternoon, at least," the weather service said.
The flood watches will remain in effect through early Saturday because of the elevated risk for flash flooding and landslides.
Western Washington state has experienced a deluge this month of "historic" flooding that prompted officials to ask about 100,000 people to evacuate last week, forced dozens of rescues and caused widespread destruction of roads and other infrastructure.
Another storm will bring heavy rain, drenching Northern California, arriving early Thursday and lasting through Friday. The storm will bring an additional 2 to 8 inches of rain, with locally higher amounts possible.
With rivers remaining high and soil saturated, the risk for more levee breaches continues over the next several days.
