BERTHOUD, Colo. – Forecasters are warning that an unstable weather pattern could bring powerful storms over the weekend to areas of Colorado that are already saturated from weeks of rain.
Violent storms across the state spawned several tornadoes Thursday and Friday, destroying homes and dropping large amounts of hail in some places — at one point forcing residents to dig out of waist-deep ice with shovels.
"We're not out of the woods yet," said National Weather Service meteorologist Kyle Fredin. "It looks like more of the same. ... We're pretty unstable. It's just what Mother Nature does."
No serious injuries have been reported from the storms that raked areas from Fort Collins in the north to Pueblo, nearly 180 miles south.
In one Denver neighborhood, residents came outside to find 3-foot-deep piles of hail. The marbles of ice blanketed the street like snow, and crews used bucket-loaders to clear the road.
In Berthoud, about 40 miles north of Denver, Alvin Allmendinger and his family scrambled to the basement just before a tornado stripped off the roof.
They stayed an hour, hail rolling down the stairs and rain seeping through the floorboards above.
Brandon Scott, Allmendinger's son-in-law, said hailstones piled up about 2 inches deep on the basement steps.
"We're all alive, and that's what matters," Allmendinger said, standing atop the rubble of the home under ominous skies.
At least three homes were destroyed in Berthoud.
On Thursday, tornadoes damaged at least six homes near Simla, on Colorado's eastern plains, Elbert County officials said. A twister touched down Friday afternoon but lifted off before causing damage, according to the National Weather Service.
More than 7 inches of rain hit parts of the Rocky Mountain foothills, which experienced devastating flooding in 2013.
Rivers in northern Colorado, meanwhile, are running high from melting snow and an unusually rainy spring, increasing the flood risk there.
The storms that began overnight Thursday were the result of the El Nino phenomenon in the Pacific Ocean, an upper-level jet stream and a low-pressure system parked over southern California. The factors have combined to deliver moisture from the Gulf of Mexico into Colorado and southern Wyoming.
Flash floods swept through the eastern Wyoming town of Lusk before dawn Thursday, wiping out a bridge on the major road through the community of about 1,500 people.
The nasty weather is expected to extend into Kansas and Nebraska on Saturday and Sunday.