Several iWitness7 viewers captured photos of shelf clouds moving into the Miami Valley, and many have asked what’s the difference between a shelf cloud and a wall cloud.
PHOTOS: Shelf cloud formations captured by iWitness7 viewers
The process creates wedge-shaped appearances. On very humid days the cloud can look ragged and dip low to the ground.
“Shelf clouds form when a cold downdraft pushes strong winds out ahead of a strong thunderstorm,” according to Storm Center 7 Meteorologist McCall Vrydaghs. “This is known as the gust front. The cool air associated with this downdraft forces warm air up and over.”
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“It is important to note these cloud formations are indicative of strong winds,” Vrydaghs said. “You will usually feel a drop in temperature along with increased winds as this cloud and storm approaches.”
Wall clouds, on the other hand, are typically rain-free and will form with a strong updraft of a supercell thunderstorm.
“This rapid rise in air creates a lower pressure below the storms main updraft, forming this wall cloud,” Vrydaghs said. “Sometimes the rotation and vertical motion within this cloud can create a tornado.”