A powerful spring storm made a wet, cold wintry mess of Mother's Day in parts of Colorado and Wyoming.
A foot of snow fell Sunday in the foothills northwest of Denver, and more precipitation in the form of a rain-snow mix was expected to greet Monday commuters along much of Colorado's Front Range.
Elsewhere, thunderstorms are expected from San Antonio to Chicago, with tornado watches issued for parts of Iowa, Nebraska, and Oklahoma. The Weather Service also said large hail could fail in central and northern Kansas through southeast Nebraska through Sunday night.
Accumulations could reach up to 15 inches of snow over part of Colorado and Wyoming by tonight, with enough force to cause power outages and treacherous driving conditions.
Wintry conditions forced the closure of a 150-mile stretch of Interstate 80 between Cheyenne and Laramie, Wyo. Snow showers are expected to linger into Monday.
The National Weather Service issued a winter storm warning for most of northern Colorado and parts of southern Wyoming for all of Sunday and for Monday morning.
The weather service also warned that snow could be heavy and wet enough to snap tree limbs and power lines, causing power failures. Winds gusting up to 30 mph could reduce visibility, and roads could be treacherous to drive.
At least one tornado touched down in northwest Missouri Saturday night, damaging scores of homes, three churches and a school in Orrick, a town of about 900 residents northeast of Kansas City. No injuries were reported.
Contributing: William M. Welch; Associated Press