Much of the nation is bracing for a massive winter storm, expected to bring "potentially historic and destructive" rain, ice and snow.
The National Weather Service predicted the storm could dump as much as two feet of snow and stretch from Colorado to New England by week's end.
About one-third of the nation and approximately 100 million people may be affected.
"A storm of this size and scope needs to be taken seriously," said FEMA Administrator Craig Fugate. "It's critical that the public does its part to get ready."
Bitterly cold temperatures were forecast in the wake of the storm, with wind chills as cold as 40 degrees below zero possible for parts of North Dakota, South Dakota and other areas.
The worst of the storm is expected Tuesday as moisture from the Gulf of Mexico feeds the huge system, causing snow and thunderstorms.