Cold Air Funnels spotted Thursday near Hermosa: What are they?
There were several sightings of cold air funnels Thursday as unusually warm air pushed through the Black Hills Region
HERMOSA, SD – Frank and Carol Foster were driving between Hermosa and Rapid City Thursday morning when they noticed this strange looking cloud and snapped a few pictures.
The pencil-like anemic looking funnel cloud descended from the base of some agitated clouds just to the East of the Black Hills. What they captured is a weather phenomena called a cold air funnel.
Cold air funnels are a far, far distant cousin of the much more recognized tornado. While a tornado forms from mature thunderstorms, a cold air funnel can form at the base of a weak thunderstorm or anemic showers.
Cold air funnels mostly form in the Spring and Fall when you still have decently warm surface temperatures, while you also have bitterly cold temperatures a few thousand feet up.
The vast majority of cold air funnels are harmless, funneling warm air quickly from the surface to colder pools of air just above.
There *have* been rare cases where these funnels have reached the surface and caused EF-0 wind damage (winds up to 85 MPH)
A close comparison to these phenomena could be waterspouts, which produce similar winds and form under somewhat similar conditions with warm surface temperatures being funneled up into cooler air. Waterspouts can form underneath robust updrafts.
There have been several sightings of cold air funnels across the Black Hills, notably at the Buffalo Roundup in Custer State Park in 2020. Given our oddly warm days during the late fall and early Spring we have the right ingredients to see this phenomena more than other places.
These are a fairly rare occurrence… so if you do manage to capture one with a camera, consider yourself lucky!