The rare deep freeze in the wake of an historic winter storm that swept across the U.S. South this week will linger through Sunday, leaving the region in the grip of extreme cold and ice and creating dangerous driving conditions.

A record-setting snowstorm along the Gulf Coast has Louisiana officials worried people unaccustomed to the cold might overreact in ways that could get them killed. Hence, a strange warning was issued during the storm: Don’t invite alligators,