A huge storm system crossing the U.S. threatens to unleash tornadoes Friday in the Mississippi Valley, blizzards in the northern Plains and dry, gusty conditions in Texas and Oklahoma that pose a high risk of wildfires.

Violent tornadoes and high winds decimated homes, wiped out schools and toppled semitractor-trailers as a monster storm that killed at least 32 people ripped its way across the central and southern U.

A sprawling storm system crossing the US on Friday caused deadly crashes, damaged buildings and fanned more than 100 wildfires in several central states, prompting evacuation orders in some communities.