At least two people are dead after a severe weather system swept through the southern United States on Christmas Day .

Tornadoes touched down in Alabama, Louisiana, Mississippi and Texas, damaging or destroying scores of homes and leaving tens of thousands of residents in the region without power. The system also caused winter storms in Oklahoma, leading to a 21-car accident on a major interstate.

Authorities in Texas say a 25-year-old man was killed when a tree toppled by high winds fell on his pickup truck as he was driving through Houston. One person was killed in a car crash on a show-covered highway in Oklahoma.

Forecasters say the weather system will move into the midwestern U.S., causing blizzard conditions in parts of Arkansas, Ohio, Illinois and Indiana.