Powerful winter storm to bring freezing temperatures, snow to much of the U.S.

A powerful Arctic cold front was slated to bring blizzard conditions to several parts of the U.S. this week, lowering temperatures to dangerous levels, dumping heavy snowfall, causing potential power outages and creating a holiday travel nightmare for millions of Americans in the process.  

The storm will extend from the Pacific Northwest to the Rockies, the Great Plains, the Great Lakes, and the central Appalachians, the National Weather Service said. It had already hit the Pacific Northwest Tuesday, canceling nearly all flights in and out of Vancouver International Airport, and dumping snow in the Cascades, leading to treacherous driving conditions. There were also dozens of delays and cancellations at Seattle-Tacoma International Airport, according to FlightAware. 

During the course of the storm, temperatures could plummet by 25 to 35 degrees Fahrenheit in "only a few hours," the weather service warned.