Outages in Iowa as season's first blizzard starts journey in the Plains Power outages affect thousands in Des Moines, Iowa (CNN) -- Tens of thousands of people lost power in Iowa on Thursday as the first major storm of the season swept in, bringing blizzards, high winds and severe thunderstorms to the central United States. The storm prompted the National Weather Service to issue a blizzard warning for a huge swath of the Midwest stretching from eastern Colorado to Wisconsin's Lake Michigan shoreline, including virtually all of Iowa. The declaration warned of snow accumulations of up to 12 inches, complemented by 25- to 35-mph winds that will occasionally gust to 45 to 50 mph. More than 30,000 people were without electricity Thursday morning in Iowa, the bulk of them in Des Moines, according to MidAmerican Energy. Iowa has seen the highest levels of snow so far, the National Weather Service said, with more than 8 inches in places. Travelers who have hit the road early for the holiday season may face challenging conditions. Gov. Scott Walker declared a state of emergency in Wisconsin ahead of the storm, mobilizing the Wisconsin National Guard, the state patrol, Wisconsin Emergency Management and other state agencies. The Wisconsin State Patrol and National Weather Service have urged people to avoid traveling. "Mobilizing our state agency resources during this storm will ensure we leave nothing to chance when it comes to protecting the citizens of Wisconsin," Walker said. In Colorado, adverse weather has closed U.S. Highway 6 at Loveland Pass, the state's Department of Transportation reported Thursday. U.S. Highway 385 was closed in the Cheyenne Wells region Wednesday but reopened Thursday, Colorado's Department of Transportation said, with warnings of high winds and icy spots. Airlines were reporting relatively few cancellations or delays in areas affected by the storm Wednesday night, but that may change Thursday. Rain will quickly change to snow as the storm advances northeast, with the heaviest snow occurring overnight. Another storm is beginning to affect the Pacific Northwest and northern California, where heavy mountain snow and coastal flash flooding are possible through at least Thursday, the National Weather Service said. At least 17 people were sent to hospitals near Lubbock after a 23-vehicle chain-reaction crash on Interstate Highway 27 north of New Deal, Texas, state safety officials told CNN on Wednesday. Meanwhile, the National Weather Service in Mobile, Alabama, issued a tornado warning until 5:30 a.m. CT on Thursday for a cell that was moving directly toward downtown Mobile. The storm has shown signs of strong rotation and could affect downtown Mobile and the Mobile Regional Airport. Storm damage reported in Alabama CNN's Jim Kavanagh, Laura Smith-Spark, Carma Hassan and Joe Sutton contributed to this report.