YouReporter Captures Photo Of 'Angry' Mammatus Clouds

DEER TRAIL, Colo. (CBS4) - Lisa Eldringhoff captured a photo of what CBS4's Jim Benemann described as "angry clouds" on May 8 west of Deer Trail at Eldringhoff Ranch.

They mammatus clouds, which CBS4 forecaster Ed Greene says is a sign of "moist and unstable air."

"If you see these clouds it means either a severe thunderstorm has been by or a severe storm is on its way," Greene said.