SEATTLE — Winter weather pounded a swath of the U.S. West on Monday, closing schools, snarling traffic and turning coastal cities like Seattle that rarely get much snow unusually white as the Midwest warmed up from a dangerous blast of cold last week.
The Pacific Northwest's first major winter snowstorm comes as parts of California and Montana brace for the threat of mudslides and avalanches and the middle of the country grapples with the fallout from the polar vortex, which is linked to at least 30 deaths in several states.
The storm hit hardest in western Washington, closing numerous schools in Seattle and nearby cities, canceling flights and ferry service, and leading to car crashes but no major injuries.
Snow was heaviest just north and east of Seattle, with 8 to 10 inches (20 to 25 centimeters) in some towns. Temperatures were expected to be 15 degrees lower than normal this week, with lows in the teens, the National Weather Service said.
Some Oregon residents also woke up to several inches of snow in northern coastal communities.
The storm system lingering over the Northwest has sent waves of snow into the Northern Rocky Mountains, where it mixed with a blast of frigid arctic air and gusting winds to create hazardous driving conditions and dangerous wind chills 40 degrees below zero and lower.
The cold closed or delayed schools Monday. Much of western and northern Montana will likely see subzero temperatures until at least Wednesday, weather service meteorologist Cody Moldan said.
"We're kind of stuck in a cold pattern," Moldan said.
The weather was warmer near Yellowstone National Park, but the fresh snow that fell on the weak snowpack in the mountains near the park led to avalanche warnings.
Snow and rain throughout California threatened flash flooding where massive wildfires roared through communities last year and dangerous driving conditions in the latest of a series of storms over the past few days.
Forecasters predicted up to 3 inches (7.5 centimeters) of rain for some parts of Southern California. Officials warned of flash flooding in the Malibu area, where a wildfire destroyed homes and burned hillsides bare. Mud carried trees and rocks onto many roads, shutting them down.
Southeast of Los Angeles, where an August blaze scorched a huge area in the Cleveland National Forest, crews removed debris and deepened a creek bed to help prevent flooding. Residents were urged to prepare to evacuate if there's flash flooding.
The weather service issued a winter storm warning for the Los Angeles and Ventura County mountains through Wednesday, with more than a foot (30 centimeters) of snow expected at higher elevations.
A winter storm that swept across California and Nevada dumped as much as 8 feet (2.5 meters) of snow over the weekend, with much more expected.
In parts of California's Sierra Nevada, officials issued blizzard and avalanche warnings through Monday night, warning that cold conditions in the northern mountain range could become life-threatening as a series of intense storms and powerful winds brought whiteout conditions that closed some mountain roads.
Electric-powered commuter trains in the Chicago area were getting back to normal as temperatures moved into the 40s. The arctic cold played havoc with overhead powerlines and forced the shutdown of two major train lines.
But cold weather again moved into Michigan's Upper Peninsula, where an ice storm created hazardous travel conditions and led schools and businesses to close. Northern Michigan University in Marquette also canceled classes. Icy conditions were expected Tuesday night and Wednesday in the Lower Peninsula, including the Detroit area.
Heavy snow and gusty winds also made travel difficult in North Dakota.
In the Northwest, Seattle-Tacoma International Airport reported at least 3 inches of snow, 62 canceled flights and 124 delayed flights.
Snow began to fall Sunday night and caused numerous crashes. The Kitsap Fast Ferry canceled service Monday because of strong winds and rough seas, and the University of Washington in Seattle and UW Bothell shut down.