The National Weather Service reported four tornado touchdowns in Watkins, East Denver and Aurora, Colo.
"This thing is spinning up multiple tornadoes," witness Jeff Piotrowski told CNN. "There were tornadoes on the outer ring of the circulation, ... and then there's the main tornado vortex closer to the storm."
Just taken in Watkins. pic.twitter.com/9tEe23uH3V— Adams Sheriff's Page (@AdamsCoSheriff) May 21, 2014
The storm system also dropped significant amounts of hail all over the Denver metro area, causing streets and yards to look like they'd been pummeled with a winter storm.
67th and TOWER (5" hail) pic.twitter.com/ME6XGwE41j— Denver Police Dept. (@DenverPolice) May 21, 2014
PUSHING STUCK CARS TOWER & PENA pic.twitter.com/fvlFmyjFcG— Denver Police Dept. (@DenverPolice) May 21, 2014
The tornado warnings prompted the closure of Denver International Airport for about an hour and a half. At least 38 flights were diverted and the airport expected delays throughout the rest of the day.