Tornadoes swept across parts of Colorado and destroyed or damaged several homes, while powerful storms brought flooding and marble-size hail to some areas. There were no reports of anyone being hurt.

At least three homes were demolished Thursday in the town of Berthoud, about 40 miles north of Denver, said Lori Hodges, director of the Larimer County Office of Emergency Management.

Crews were checking on reports of about 25 other homes that were possibly damaged or destroyed, but they were hindered by foul weather and darkness.

"The rain is so heavy in that area with hail that they are not able to get more damage assessments," Hodges said.

The National Weather Service said the tornado was first spotted early in the evening east of Lyons.

The National Weather Service said at least two other tornadoes touched down in the afternoon near the tiny town of Simla, about 60 miles southeast of Denver. Elbert County officials said at least six homes were damaged there, one severely.

Hodges said flooding was a concern in Larimer with pelting rain expected to continue into the night. The area is still recovering from devastating floods in 2013.

Late Thursday, a strong storm system moved north through Denver, bringing heavy rain and hail the size of quarters.

The National Weather Service declared a flash flood emergency in Boulder and Larimer Counties until 4 a.m. Friday and urged residents in low-lying areas to move to higher ground and be prepared to evacuate.

Scott Oliver, who lives in northern Boulder County, told The Daily Camera newspaper he went to move his car because of hail when he saw the tornado touch down.

"It was probably on the ground two minutes," he said. "It was just kicking up everything. It was terrible."

Oliver said that when he saw a piece of roof go flying by, "it was clear it packed a punch.

"When the roof blew by, we knew it was serious," he said, adding that his neighbor was forced to dive beneath a tractor and then into a ditch as the tornado approached.

The Red Cross was responding Thursday night to help people who have been displaced. Meanwhile, Boulder County sheriff's deputies were helping assess the damage and asking that people stay out of the area, Cmdr. Heidi Prentup said.

Forecasters had warned that the Front Range and the Eastern Plains could experience severe weather Thursday.