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A horseshoe cloud in 2016

A horseshoe cloud is a relatively uncommon meteorological phenomenon [1] which manifests as a cloud in the shape of a horseshoe or inverted letter "U". [1] [2]

They occur when a horseshoe vortex deforms a cumulus cloud. [2] The clouds are relatively short-lived [2] and is the last stage before one dissipates. [3] Horseshoe vortex clouds are a form of "fair-weather" funnel cloud and are similar to the shear funnel type of funnel cloud.[ citation needed]

A March 2018 instance was explained by the United States National Weather Service: [4] [5]

As the updraft pushes flattish cumulus clouds up & a horizontal vortex develops from differential updraft speeds... As the vortex climbs, it's caught in the faster horizontal winds aloft, & the middle part of the vortex catches the faster speeds with the ends being slower.

These clouds do not occur often because all the needed conditions rarely occur together. [3]

References

  1. ^ a b "Horseshoe Vortex Cloud (February 07)". Cloud Appreciation Society. January 31, 2007. Retrieved March 12, 2018.
  2. ^ a b c "An incredibly rare 'horseshoe cloud' was spotted in Nevada and it kept the meme-makers busy". Independent.ie. March 12, 2018. Retrieved March 12, 2018.
  3. ^ a b Baer, Stephanie K. (March 10, 2018). "People On Twitter Are Freaking Out Over This Rare Type Of Cloud". BuzzFeed News. Retrieved February 2, 2023.
  4. ^ @NWSElko (March 9, 2018). "As the updraft pushes flattish cumulus clouds up & a horizontal vortex develops from differential updraft speeds..." ( Tweet) – via Twitter.
  5. ^ @NWSElko (March 9, 2018). "As the vortex climbs, it's caught in the faster horizontal winds aloft,& the middle part of the vortex catches the faster speeds with the ends being slower" ( Tweet) – via Twitter.