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."
The National Weather Service hazardous weather outlook Saturday for eastern Utah and western Colorado, warns:
Isolated strong to severe storms are possible in the four Corners region this afternoon with a threat of hail. Strong winds and a possible funnel cloud or tornado. Widespread rain showers with scattered embedded thunderstorms will affect much of eastern Utah and western colorado today and tonight. Heavy rain may cause small streams and washes to rise rapidly...And dirt or unimproved roads in rural areas may become impassible
No serious injuries have been reported from the earlier 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.
The Weather Channel tweeted a picture of a street that was so covered in hail, it looked like there had been a recent snowfall. The hailstones still covered the road as of Friday morning.
According to the Associated Press, Berthoud, Colo., was the hardest hit by the storm. Three homes were destroyed by a tornado and 25 others may have been damaged, but no injuries were reported.
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.