Officials are rushing to reschedule Mardi Gras celebrations and warning revelers against brining umbrellas and tents as powerful storms with a threat of tornadoes are expected to strike Louisiana and other parts of the South.

More than 55 million people across the central and southern US are at risk of severe weather on Tuesday as a violent storm sweeps across the country, bringing the potential for blizzard conditions, tornadoes and fire weather.

The city’s two biggest parades are set to go on with earlier start times, shorter routes, and no marching bands, New Orleans Police Superintendent Anne Kirkpatrick told reporters Monday.