A powerful winter storm that has left at least 7 dead and spawned winter weather alerts spanning 1,500 miles is targeting the nation's capital on Sunday, bringing the region its biggest amount of snow so far this season.

The National Weather Service said that the heaviest snow threat has shifted into the Mid-Atlantic, where 5 to 12 inches of snow is expected through Sunday night. Between 8 to 12 inches of snow is expected near Washington, D.C., with "locally higher amounts" possible.

"To the south, freezing rain is expected into Sunday near and east of the central and southern Appalachians, where up to a quarter of an inch of ice could accrete, with locally higher amounts possible," the NWS's Weather Prediction Center said.

MONSTER SNOWSTORM TO SPAN HALF THE US

The storm moved into Kansas and Nebraska from the Rockies on Friday, then east into Missouri, Iowa, Illinois and Indiana, covering roads and making driving dangerous.

Part of Interstate 44 near St. Louis was blocked for several hours Saturday, and at one point the Missouri State Highway Patrol warned of traffic delays as long as eight hours.

Authorities in Kansas said at least 3 people died in crashes on slick roadways, while at least 4 deaths were reported by authorities in neighboring Missouri.

"PLEASE DO NOT TRAVEL," authorities warned Saturday on Twitter. "While roads are improving, many are still snow covered."

As the storm headed east, states such as Maryland and Ohio declared snow emergencies to limit travel.

"Above all, please put safety first and communicate with your neighbors, family and friends," Russ Strickland, executive director of the Maryland Emergency Management Agency, told FOX5 DC.

Virginia Gov. Ralph Northam also declared a state of emergency Saturday night in order to allow the state to be better prepared to respond to the storm.

AT LEAST 5 KILLED IN CRASHES RELATED TO POWERFUL WINTER STORM

Missouri had gotten the worst of the storm by Saturday, with the National Weather Service reporting more than a foot of snow Saturday morning in some places around St. Louis and Jefferson City, and more than 18 inches in Columbia.

Missouri troopers responded to more than 3,000 calls for help through early Saturday afternoon, including more than 700 crashes and 1,300 stranded vehicles. Illinois State Police said troopers along the Mississippi River across from St. Louis have responded to more than 100 crashes during the storm.

"We're anticipating still more snow through today, so we're asking motorists to stay home until the roads are cleared," Missouri State Highway Patrol Sgt. Collin Stosberg, stationed in suburban Kansas City, told the Associated Press. "If you do have to get out on the road, we're asking you to do three things: Have your cellphone fully charged, wear your seat belt and slow your speed for the conditions."

At Lambert International Airport in St. Louis, most flights were canceled or delayed on Saturday.

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In central Missouri, officials said about 12,000 households and businesses were without power in Columbia and the surrounding area at one point.

The Associated Press contributed to this report.