A powerful storm has begun to unleash heavy snow and blizzard conditions across the north-central United States, prompting severe weather warnings, school closures and major road closures.

Meteorologists say the storm could dump between 6-12 inches from central Nebraska to northeastern Minnesota, according to the National Weather Service, which added that, in heavier bands, snow could fall at rates of 1-2 inches per hour.

"Heavy snow and gusty winds approaching 50 mph will produce blizzard conditions with near zero visibility into early Tuesday," the weather service warned. "Travel could be nearly impossible. Power outages and tree damage are likely in some areas due to the heavy and wet snow combined with icing and strong winds."

Schools shuttered, major roadways closed

The storms already have created disruptions and closures. South Dakota State University announced the campus will be closed through Monday night. And many school districts across South Dakota, Nebraska, and Wisconsin announced classes were either canceled or delayed.

The blizzard conditions have also prompted authorities to close parts of major highways, including Interstate 80, which runs across the country from San Francisco to New Jersey and cuts through southern Nebraska.

"Road conditions and visibility are poor in many areas of the state," the South Dakota Highway Patrol said in a statement Monday morning. "If you don’t have to travel today, don’t!"

Tornadoes and severe weather possible for the South

Across the Mississippi Valley and central Gulf Coast, thunderstorms capable of producing tornadoes are anticipated Monday night and early Tuesday, the National Weather Service said.

Tornadoes and damaging winds are possible from parts of east Texas through the Lower Mississippi Valley, according to the Storm Prediction Center. Heavy rain and flash flooding could stretch as south as Alabama, Georgia and the Florida Panhandle. Wind advisories warning of gusts potentially knocking down trees and causing power outages were issued from east Texas and northern Florida to Missouri and West Virginia.

Meteorologists anticipate the storm's major impacts to subside by Wednesday, the weather service said.

Meanwhile in the Northeast, more than 90,000 households were still without power after a powerful storm dumped over 20 inches of snow in some areas over the weekend, according to a database maintained by USA TODAY.

Contributing: Ken Alltucker