The Denver area was struck by five tornadoes today, thanks to a massive supercell thunderstorm.

The town of Aurora, CO was tormented by three twisters within a half-hour period, while two tornadoes touched down in nearby areas.

The wacky weather also brought lots of hail, and caused Denver to remain under a tornado watch until 8 pm local time.

Additionally, the threat of tornadoes also caused officials at Denver International Airport to divert 40 flights.

Colorado isn’t exactly a hotbed for tornadoes and other types of extreme weather. The state is also just outside of the “Tornado Alley,” which stretches from Texas to South Dakota and accounts for about one fourth of all U.S. tornadoes. The city does see a few twisters a year, but this behavior is quite uncommon.

67th and TOWER (5" hail) pic.twitter.com/ME6XGwE41j

— Denver Police Dept. (@DenverPolice) May 21, 2014

TOWER RD & GREEN VALLEY RANCH BLVD pic.twitter.com/gE2dtEMz79

— Denver Police Dept. (@DenverPolice) May 21, 2014

Terrifying image of a #tornado warned storm wrapping around #Bennett Colorado Watch LIVE at http://t.co/UXr1KEDmLv pic.twitter.com/abg4MyQxv9

— Daniel Shaw (@DanielShawAU) May 21, 2014

NEW PHOTO: via @WCL_Shawn: Impressive –> RT @MikeOlbinski: Tornado warned storm west of Bennett, Colorado pic.twitter.com/sq4UZChjtO

— NewsBreaker (@NewsBreaker) May 21, 2014

“This thing is spinning up multiple tornadoes,” said a witness. “There were tornadoes on the outer ring of the circulation, and then there’s the main tornado vortex closer to the storm.”

A supercell thunderstorm is characterized by the presence of a mesocyclone: a deep, persistently rotating vertical draft. The term “supercell” refers to the classification of a thunderstorm, and is one of four. Supercells are the overall least common and have the potential to be the most dangerous. Supercells make up a majority of what is seen along Tornado Alley.

Image via Adams County Sheriff, Twitter