(CNN) — A deadly winter storm in California now threatens tornadoes in the South and heavy snow, sleet and freezing rain in the Midwest.
More than three million people are under a tornado watch as of 10 p.m. Miami time in parts of Arkansas, Texas, Louisiana and Oklahoma.
And tornadoes aren’t the only risk in the region. The Storm Prediction Center warned of the possibility of hail and hurricane-force winds of up to 110 km/h “until late at night in much of the area.”
Anyone in tornado risk areas should seek safe shelter immediately, said Brad Bryant, meteorologist-in-charge for the National Weather Service office in Shreveport, Louisiana.
“If you wait for a warning to be issued, it’s too late,” Bryant said Monday. “You have to have a safe haven plan in place before these storms.”
Bryant encouraged those who need help — especially those living in mobile homes — to contact local emergency managers or law enforcement to find out what shelter options they have.
“Since mid-November we’ve had three rounds of severe weather and we’ve had fatalities, mostly in mobile homes,” Bryant said.
From Missouri to the Gulf Coast of Mexico, more than 30 million people are at risk of severe weather Monday, according to CNN meteorologist Dave Hennen.
And more tornadoes and damaging winds are possible Tuesday across parts of Louisiana, Mississippi and Alabama as the storm moves east.
Farther north, more than 15 million people from Utah to Wisconsin are under a winter weather alert Monday.
The same storm system brought record rainfall and deadly flooding to drought-stricken California over the weekend. And another wave of heavy rain this week could exacerbate dangerous flooding.
“Travel will be dangerous, if not impossible”
Rapid snowfall of 1 to 2 inches per hour is forecast across the Plains and Midwest from Nebraska to southwestern Minnesota, leaving a total of more than 12 inches of snow by the end of Tuesday. The snow avalanche could be accompanied by thunder.
“These intense rates combined with gusty winds will produce areas of drifting and swirling snow, resulting in snow-covered roads, reduced visibility and difficulty traveling,” the Weather Prediction Center said.
A significant buildup of ice could lead to power outages and treacherous travel conditions.
Freezing rain could cause a buildup of more than half an inch of ice from northeastern Nebraska to northwestern Iowa to southern Minnesota by late Monday through Tuesday.
“Travel will become dangerous, if not impossible, later tonight (through) Tuesday in many areas,” the National Weather Service in Sioux Falls said Monday.
California could see more flooding this week
Northern California communities submerged in massive flooding over the weekend could experience even more precipitation in the coming days.
It is unclear how far this storm will dent the drought conditions that have gripped California, which had its driest start to the year on record in 2022 and ended with flooded roads and swollen rivers.
“Early precipitation forecasts for the midweek storm appear to be around 2 to 3 inches possible in the Central Valley,” the weather service office in Sacramento said.
An atmospheric river – a long, narrow region in the atmosphere that can carry moisture thousands of miles – fueled a parade of storms over the weekend, bringing record rainfall and triggering water rescues.
At least two people died, including one found inside a submerged vehicle in Sacramento County and a 72-year-old man struck by a falling tree in a Santa Cruz park, authorities said.
Now, another atmospheric river could bring heavy rain and more flooding Wednesday to northern and central California, including the Bay Area.
This upcoming storm “looks like it will lead to dangerous situations,” the National Weather Service in San Francisco said.
Authorities urged residents to avoid driving in standing water.
Highway 99 remains CLOSED between@CityofGaltand Grant Line Road just south of@CityofElkGrovedue to flooding of the Cosumnes River. The roadway won’t reopen until the water recedes, which is expected sometime tomorrow afternoon.@CaltransHQ pic.twitter.com/TjFo670tul
—Caltrans District 3 (@CaltransDist3) January 1, 2023
Flooding from the Cosumnes River forced the closure of Highway 99 south of Elk Grove in Sacramento County, the California Department of Transportation tweeted Sunday. “SR 99 is one of the busiest corridors in the state, and commercially important,” its website said.
In recent days, “dozens and dozens” of people had been rescued, Cosumnes Fire Department Capt. Chris Schamber told CNN affiliate KCRA. Aerial images of the station showed cars submerged in water up to the door handles.