A Pacific storm uncoiling itself over California with heavy rain and snow is forecast to deliver a severe risk for tornadoes, high winds and thunderstorms across parts of Mississippi, Louisiana and Arkansas by the middle of next week.

Upwards of 2 inches of rain could drop suddenly in the valleys of Southern California on Saturday into Sunday with up to 6 inches in coastal foothills and mountains, touching off floods and landslides, the U.S. National Weather Service said. Then snow could fall by the foot in the Sierra Nevada range, as well as in parts of Oregon and Washington.

The tornado threat comes almost a year after a series of tornado outbreaks in the Midwest killed at least 75 people and destroyed an Amazon delivery station in Illinois. Since 1980, there have been a total of 182 severe storms and major winter storms that have caused at least $1 billion in damage and killed at least 3,296 people, according to the U.S. National Centers for Environmental Information.

There is a lot of springlike air across the central U.S., and when the powerful winter storm hits, that will touch off the dangerous weather across the South, said Bob Henson, a meteorologist and author with Yale Climate Connections.

The storm will then cross the Rocky Mountains and intensify in the Great Plains to potentially bring blizzard conditions and days of heavy snow from Montana across to the Dakotas and Nebraska, said Marc Chenard, a senior branch forecaster at the U.S. Weather Prediction Center.

The potential for tornadoes, damaging winds and flooding rainfall will spread from Texas across the South. After that the system will likely continue toward the East Coast by Thursday and Friday, though it isn’t clear what the impact will be, Chenard said.