Shelf Cloud

Shelf Cloud

The shelf cloud is one of the most misidentified clouds types; they are often mistaken for wall clouds.  There are many stark differences between a shelf cloud and a wall cloud that makes either of them easy to identify.  A shelf cloud can be found at the leading edge of a storm while the wall cloud, if it is present, will be located on the back side and along the base of the storm just behind the rain.  A shelf cloud is caused by strong downdrafts of air that originate from near the top and front of the storm; these downdrafts bring cool air and plenty of rain.  A wall cloud is caused by strong updrafts at the rear of the storm.  There is often a strong cool wind gust that precedes the approach of a shelf cloud; this wind is referred to as straight-line winds or a gust front and can cause damage depending on the strength of the downdrafts.  Due to the jagged appearance of a shelf cloud, there are often false Tornado Warnings issued as it approaches.  Knowing the difference between a shelf cloud and a wall cloud will help you respond appropriately if you are in their path.

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