A bomb cyclone slammed into the Pacific Northwest at hurricane force overnight, toppling trees, knocking out power to hundreds of thousands of people and killing at least two people.

ABC News reported that a woman was killed Tuesday when a tree fell into a home in Bellevue, Washington, while she was showering. Another woman was killed Tuesday evening in Lynnwood, Washington, when a tree fell on a homeless encampment, officials there said.

Nearly 500,000 customers were without power in Washington state as of Wednesday afternoon, according to PowerOutage.us.

The National Weather Service said winds of up to 100 mph were recorded off the coast of British Columbia, with gusts of up to 75 mph in inland Washington.

‘Atmospheric river’ on the west coast

Although the high winds were expected to subside, a subsequent “atmospheric river event” is expected to bring heavy rain and snow to much of Northern California, Oregon and Washington for several days.

“Combined with heavy snow at higher elevations, snowstorms are forecast throughout the Washington Cascades,” the weather service said.

The bomb cyclone was one of two storm systems to hit much of the United States as millions of Americans prepare to travel next week for the Thanksgiving holiday.

• Read more from Yahoo Life: How to stay safe and warm in winter: expert tips for your home, your car and your family

Near blizzard conditions in the plains

A second system — which brought severe thunderstorms to the central and southern Plains on Monday and spawned a tornado in Oklahoma — will collide with Arctic air as it moves north, causing widespread snow in the Dakotas, Minnesota and Wisconsin.

Heavy snow and gusty winds will produce near-blizzard conditions across the northern Plains on Wednesday, the weather service said, with the heaviest amounts of snowfall forecast in North Dakota, eastern South Dakota and northwestern Minnesota.

• Read more from Foxweer: Snow and rain will lash the US as winter storms intensify ahead of Thanksgiving travel

Snow from the mid-Atlantic to the northeast

In addition, a higher-level low-pressure system was forecast to develop over the Great Lakes later this week, resulting in cooler temperatures, cold rain from the Ohio Valley to the East Coast and accumulating snow for the central Appalachians, the weather service said.

Winter weather warnings have been issued from the mid-Atlantic to the Northeast, where up to a foot of snow is possible Thursday and Friday, especially in the higher elevations of West Virginia and Maryland.

While most people in the Northeast and New England will see rain, at least four inches of snow are expected to fall in parts of northeastern Pennsylvania and New York’s Catskill Mountains through the end of the week, the weather service said.

What about Thanksgiving?

Weather service forecasters have yet to issue forecasts beyond seven days, but the U.S. Climate Prediction Center’s six- to 10-day outlook points to above-average chances of rain in the Pacific Northwest, upper Midwest and Great Lakes early next week. .

Nearly 80 million people are expected to travel more than 50 miles for Thanksgiving next week, with Tuesday and Wednesday expected to be the busiest times on the roads, according to AAA.

• Read more from NBC News: Nearly 80 million people are expected to make record-breaking trips this Thanksgiving