These photos were taken by Jorn Olsen, he lives on Heartwell Park

in Hastings, Nebraska.

Spectacular Mammatus Clouds

over Hastings, Nebraska

 December, 6th, 2004

Three of these extremely rare photos were featured on the front

and back cover of the Journal of Meteorology and circulated in 26 countries.

UNL University of Nebraska-Lincoln High Plains Regional Climate Center

UNL University of Nebraska-Lincoln High Plains Regional Climate Center

Mammatus Clouds

Mammatus are pouch-like cloud structures and a rare example of clouds in sinking air.

Sometimes very ominous in appearance, mammatus clouds are harmless and do not mean that a tornado is about to form; a

commonly held misconception.

In fact, mammatus are usually seen after the worst of a thunderstorm has passed.

Mammatus typically develop on the underside of a thunderstorm's anvil and can be a remarkable sight, especially when sunlight is

reflected off of them.