(CODEWIT) — A snow storm is rolling into the Plains states Thursday, triggering winter storm warnings and watches in an area covering 800,000 square miles in 18 states.
About 30 million people live in its path.
Dodge City, Kansas, "is in the middle of a bull's eye," said CNN Meteorologist Chad Myers. The state should see 16-18 inches of snow west of Wichita and up into Nebraska.
Kansas State University canceled Thursday classes, as have dozens of grade schools in the Plains states. Kansas City International Airport advised passengers to check their flight status before heading to the airport.
CNN affiliate KSNW in Wichita reported that crews had treated roads Monday, but no matter how much salt and sand they spread, by Wednesday morning primary roads were snow-packed and slick. Side streets were worse.
On Wednesday the system left a rare thin layer of snow across the deserts of Arizona, New Mexico and Southern California — as far south as the border with Mexico.
A large system
The storm system is huge and also has a warmer, wetter Southern component.
It will eventually stretch from the Dakotas to Houston, Texas, Myers said. While it will remain snowy in the north, it will spawn torrential rains and tornadoes along the Gulf Coast.
It will also dump freezing rain over Arkansas and Missouri, Myers said.
"There's going to be a monster ice storm over Springfield (and) Branson, Missouri. Think of an inch of ice coating everything," he said. "Power lines will be coming down. Trees will be coming down."
In St. Louis, freezing rain is predicted to fall on top of a thin layer of snow, having "a significant impact on travel," the National Weather Service warned.
North of where the most snow will fall, Chicago could receive as much as 4 inches, Myers said.
Severe thunderstorms moving in from the Gulf of Mexico are expected to dump from 2 to 6 inches of rain over New Orleans and Montgomery, Alabama, according to CNN's weather center, before rolling up toward Atlanta.
The torrential rains could lead to significant river flooding, as flood watches are still in effect from last week's heavy rains.
Heavy winds, hail and tornadoes are possible, the National Weather Service says. Downpours are expected to continue into Friday.
CNN Meteorologists Chad Myers and Pedram Javaheri contributed to this report.