(Reuters) - A major storm system brought a mix of bad weather on Tuesday to much of the central United States, with a band of tornadoes downing trees in Alabama and Mississippi and heavy snow blanketing the northern Midwest.

The National Weather Service said eight tornadoes had hit eastern Mississippi and another had struck western Alabama, with another two possible in the state. The Mississippi storms had blown roofs off, flipped mobile homes and downed trees, it said.

Emergency officials in Alabama’s Pickens and Fayette counties said the tornadoes had downed trees and power lines, with some structures damaged.

“At this point there are no major injuries or fatalities, which is a blessing,” said Pickens County Engineer Sky Hallmon.

The National Weather Service said more tornadoes were possible in Alabama through the evening. Tornado watches were in effect for central Tennessee and central Kentucky, which means conditions exist for a possible tornado

Winter storm and blizzard warnings were in place from the central Rocky Mountains to northern Michigan, the NWS said. Northern Wisconsin and Michigan are forecast to receive the highest amounts, with up to 12 inches (30 cm) of snow, according to the National Weather Service.

St. Paul and Minneapolis, Minnesota, have declared a snow emergency, with parking restrictions, while state government offices in several counties of southeast South Dakota closed early on Tuesday due to snow and high winds.

Stormy weather has affected U.S. air travel, with 2,419 flight delays and 721 cancellations, with airports in Minneapolis, Chicago and Denver hit the hardest, according to the FlightAware website.