ARAPAHOE COUNTY, Colo. (KDVR) — Update 7 p.m. The National Weather Service confirmed the weather phenomena spotted at Interstate 70 near E-470 was a landspout.
Earlier: A tornado was spotted and reported to the National Weather Service that was later identified by the Pinpoint Weather Team as a dust devil.
A tornado warning was issued for Adams and Arapahoe counties until 4:45 p.m. and Pinpoint Weather Meteorologist Dave Fraser said this was likely a dust devil that was seen. The Adams County warning was canceled shortly after it was issued but the Arapahoe County warning remained in effect.
Video taken by Donovan Kelly shows the dust devil from Interstate 70 in the player above.
What is a dust devil and how is it formed?
Pinpoint meteorologist Chris Tomer explained that, unlike tornadoes, landspouts are not always associated with thunderstorms. They often form from large dust devils. Due to their ability to form without a storm present, they can occur on days when no severe weather is in the forecast.
Dust devils can spin up under a blue sky as warm, dry updrafts of air (known to pilots as thermals) become organized into a vortex. Sometimes they can be pulled into the base of a weak thunderstorm cloud, or just a puffy, cumulus cloud, by the larger-scale updraft. Essentially the dust devil feature joins with the cloud to create what appears to be a tornado.
Thunderstorms across the Front Range
Scattered showers and thunderstorms will move across metro Denver and the Front Range through the early evening hours on Friday. A few storms could produce heavy rain. The biggest threat for flooding will be in the foothills west of Denver across old wildfire burn scars.
A flash flood warning was issued this afternoon in Larimer County over the Cameron Peak burn scar after a half inch of rain fell in 15 minutes. So far, no flooding damage or injuries have been reported.