Finger on the Weather

International agency unveils new cloud names

Wall clouds have a new name – murus – in the International Cloud Atlas released Thursday. It’s the first update to the atlas in 30 years. This wall cloud formed in the Wichita area on July 3, 2005.
Wall clouds have a new name – murus – in the International Cloud Atlas released Thursday. It’s the first update to the atlas in 30 years. This wall cloud formed in the Wichita area on July 3, 2005. File photo

For the first time in 30 years, new names for various cloud formations have been approved.

The World Meteorological Organization will release its new International Cloud Atlas on Thursday, which is World Meteorology Day.

The atlas includes five new cloud names and a new cloud “species,” officials say. Residents of Tornado Alley will be familiar with the new species and at least a couple of the formations that have been given new names.

The new species has been dubbed volutus, which is more commonly referred to by meteorologists as roll clouds. Those horizontal clouds are detached from thunderstorms and are at lower levels of the atmosphere.

Volutus is Latin for “rolled,” which, as Chris Dolce wrote on the Weather Underground website, “perfectly matches their appearance.”

I remember watching a roll cloud move over the family farm when I was a child. It was both scary and captivating, though ultimately harmless.

Two cloud names that residents of the Great Plains may start to hear more often are murus and clauda. Murus is another name for a wall cloud, while clauda is another name for a tail cloud.

Both are key elements of supercell thunderstorms, which are capable of producing tornadoes. The wall cloud, a lowering in the cloud base, is where the tornado most commonly forms, while the tail cloud is a feature extending away from the wall cloud.

The tail clouds are an indication of air feeding into the storm and also are a clue as to the direction the storm is moving.

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