DENVER -- A microburst is being blamed for causing damage in parts of the metro area Thursday afternoon.

The roof of the Alameda East Veterinary Clinic in Denver was blown over by the strong straight-line wind event.

Employees said that at about 2 p.m., they saw the wind blowing the trees and then heard a loud rumbling noise. It was the howl of the roof being peeled off the building and thrown into the middle of the road.

Part of the mangled white metal landed on the clinic's animal lodge, but the dogs had been evacuated in time. No animals or people were hurt.

A little further west on Alameda Avenue, the winds uprooted a large 80-year-old tree, which snapped in two when it landed on a nearby fence.

Massive trees all over the metro area were knocked down. Some landed on power lines, forcing thousands to go without power briefly.

Others landed on cars and a few landed on homes. It's not known how extensive the damage has been to homes.

There were no reports of injuries from the falling trees.

Mary Machado, a 7NEWS viewer said, "One of the microbursts hit at the Bishop Machebeuf High School baseball field. A very large set of bleachers were literally picked up and thrown into the backstop. There was a game in progress, but fortunately few spectators and no one was injured."

Storm damage was reported in Denver.

The winds also blew down a wall at a construction site at 6th and Colfax, spraying debris everywhere as it crashed down.

The storms were small but they packed a punch.

"It was sound and fury but signifying not really much of a storm," said 24/7 Meteorologist Mike Nelson.

Nelson said the microburst was caused by warm temperatures and a limited amount of moisture.

"What happened was a microburst. High-based thunderstorms have moist air aloft and dry air near the ground. The rain tends to evaporate before it reaches the ground and that evaporation causes cooling, which causes the air to become heavier or more dense. It drops down to the ground to the base of the thunderstorm and can rocket out at speeds of up to 40 to 60 mph," said Nelson. "It's a divergent pattern. In other words, it flows out and away from the storm, unlike a tornado, which tends to have a swirling wind pattern."