Blizzard barrels through U.S. Great Plains, threatening new floods

By Keith Coffman

By Keith Coffman

DENVER (Reuters) - A "bomb cyclone" blizzard swept out of the Rockies into the Great Plains on Wednesday, leading the Colorado governor to activate the National Guard and prompting fears of more flooding in areas still recovering from a deluge last month.

Warm spring temperatures on Tuesday gave way to heavy snow, gale-force winds and life-threatening conditions on Wednesday across a swath of the central United States running from Colorado to Minnesota, the National Weather Service said.

"This is potentially a life-threatening storm," said Patrick Burke, a meteorologist with the NWS Weather Prediction Center in Maryland.

In March, a late-winter "bomb cyclone," which involves a rapidly intensifying cyclone, triggered heavy rainfall over the region and combined with melting snow to cause extensive flooding along the Missouri River and its tributaries. The deluge resulted in more than $3 billion in damage to property and crops in Nebraska and Iowa alone.

This week's storm also qualified as a bomb cyclone and could lead to further flooding, said Weather Prediction Center meteorologist Marc Chenard.

Colorado saw a huge temperature swing, with the state capital of Denver basking in 80-degree Fahrenheit (30-Celsius) weather on Tuesday, before snow fell on the city on Wednesday and temperatures dropped to 30 F (minus 1 Celsius), meteorologists said.

The slow-moving storm on Wednesday dumped snow on parts of Colorado, Wyoming, South Dakota, North Dakota, Wyoming, Minnesota and Wisconsin, Chenard said by phone. Some areas had already received more than 1 foot (30 cm) of snow.

CLOSING STATE OFFICES

Officials in Colorado and South Dakota closed state offices on Wednesday and urged people in all areas affected by the blizzard to consider leaving work early.

Colorado Governor Jared Polis activated the National Guard, which planned to deploy 24 vehicles, including tactical trucks, for possible missions to rescue stranded people, the agency said in a statement.

Residents throughout the north-central United States could expect downed trees, widespread power outages, road closures and treacherous driving conditions, Burke said.

Some areas of western Minnesota and southeast South Dakota could see as much as 30 inches (76 cm) of snow before the blizzard winds down.

Compared to last month's bomb cyclone, the precipitation this time has come in the form of snow rather than rain, slowing the runoff process.

But the threat of flooding will emerge as the snow melts, Chenard said.

Areas in South Dakota and Iowa surrounding the Missouri River are still in flood stage following last month's severe weather, he said.

"The system will cause some additional rises on several of the rivers in the area," Chenard said.

More than 700 flights were canceled at Denver International Airport on Wednesday, according to FlightAware.com, an airline tracking website.

The weather system is expected to weaken and move to the Great Lakes area and northern Michigan on Friday, bringing rain and snow to that region, the Weather Service said.

(Additional reporting by Andrew Hay in Taos, New Mexico, Rich McKay in Atlanta, Gina Cherelus in New York and Alex Dobuzinskis in Los Angeles; Editing by Bill Tarrant and Cynthia Osterman)