DENVER (REUTERS) - A "bomb cyclone" blizzard, the second in a month, hit the Rockies on Wednesday (April 10) and spun into the US Plains and Midwest, bringing fears of more flooding in areas still recovering from last month's deluge.
Warm spring temperatures on Tuesday, upwards of 26.6 deg C in Denver, gave way to frigid -6 deg C, heavy snow, gale-force winds and life-threatening conditions, the National Weather Service said.
"It is a bomb cyclone, the second we've had," said Mr Brian Hurley, a meteorologist with the weather service's Weather Prediction Centre in Maryland. "This is like a slow-moving snowstorm inside a hurricane."
Wind gusts upwards of 160.93kmh were reported on Wednesday in eastern Colorado, Mr Hurley said.
Denver International Airport reported that about half its flights, 755, were cancelled on Wednesday and into early Thursday, but all runways remained operational.
Residents throughout the north-central United States could expect downed trees, widespread power outages, road closures and treacherous driving through Friday, the NWS said.
More than 10,000 homes and businesses were without power in South Dakota early on Thursday, according to the tracking site PowerOutage.us.
In March, another "bomb cyclone," which involves a rapidly intensifying cyclone, triggered heavy rain over the region and combined with melting snow to cause flooding along the Missouri River and its tributaries. More than US$3 billion (S$4.06 billion) in damage was done to property and crops in Nebraska and Iowa alone.
This week's storm will keep dumping snow on parts of Colorado, Wyoming, South Dakota, North Dakota, Minnesota and Wisconsin throughout the day, meteorologist Hurley said.
"The heaviest snow so far is piling up in South and North Dakota, with some areas getting 17 inches (43.2cm), and more is on the way," he said. "We're expected another 10 to 15 inches before this is done."
That snow adds to the woes of the Midwest farmlands, which in recent weeks saw record flooding that washed out crops and drowned cattle.
"All that snow is going to melt sooner rather than later, and it'll all flow into the Missouri River basin," Mr Hurley said.
The weather system is expected to weaken and move to the Great Lakes area on Friday, bringing rain and snow to that region, the Weather Service said.