SYRACUSE, N.Y. (WSYR-TV) — Once again pictures came flooding into our inboxes Thursday evening. This time it was pictures of a shelf cloud that raced north through CNY.

Shelf clouds are associated with severe thunderstorms and usually are responsible for locally gusty and perhaps damaging winds. There were a few power outages associated with some of the damage with these thunderstorms.

Shelf cloud by Scott Morin, Liverpool

How does it form?

Basically, cold air descending in the thunderstorm hits the ground and essentially splashes forward of the storm. (Think of pouring a bucket of water onto a table. The downdraft behaves much like the water)

Warm and humid air in advance of the severe thunderstorm line is forced upward by the rush of cold and dense air. As that warm and humid air rises it condenses and forms the shelf cloud.

It almost looks like a spaceship – Dave Longley, meteorologist

The shelf cloud is the leading edge to the cooler, damaging wind.

Sometimes the sky behind the shelf cloud can take on a greenish tint and this is usually indicative of hail within the thunderstorm.