A powerful storm system is producing whiteout conditions in portions of the central United States and nearly 7 million people are under a tornado watch as residents in parts of the Plains remain under a threat for dangerous 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.

On Monday, 8 million people were under winter storm watches and warnings, although the storms' impacts were less severe than those over the weekend.

Dust storms are raging across much of New Mexico. The National Weather Service pushed emergency alerts to cellphones that warned of zero-visibility road conditions and adverse health consequences for infants and the elderly.

Another round of intense dust storms led to multiple crashes and at least three injuries along New Mexico highways and interstates Tuesday, officials said.