Like giant breakers in the ocean surf, magnificent cloud waves in the sky crested and crashed above Virginia’s Smith Mountain Lake on Tuesday evening.
These rare clouds, known as Kelvin-Helmholtz instability waves, were spotted and photographed by Amy Christie Hunter around 8:30 p.m.
“It was the coolest cloud formation I think I’ve ever seen!” she wrote on her Facebook page . “It was so amazing.”
Hunter’s photo has gone viral, appearing on local and national television news broadcasts and websites.
Kelvin-Helmholtz instability clouds form from variation in air density between adjacent layers and the resulting difference in wind speeds known as shear. These clouds are extremely short-lived, and they break in the same fashion as a wave on a shore — as the bottom layer moves slower than the top layer, and the top billows over and crashes.
To initiate these wave clouds, you need a perturbation or disturbance to jostle the air flow. Usually, they last just 10 minutes or so before collapsing.
They’re most common near mountain ranges because of the stratified air above them, but they can form anywhere and show off the fluid nature of the atmosphere.
Here are two other textbook examples of these cloud formations, both from 2015:
From Breckenridge, Colo.
Kelvin-Helmholtz clouds tower over Breckenridge Ski Resort in Colorado on Oct. 28, 2015. (@breckenridgemtn) From the Galápagos Islands:
View over San Cristobal Island in the Galápagos aboard ship Celebrity Xpedition on July 24, 2015. (Chris Miller) More on Kelvin-Helmholtz wave clouds
Wicked cool wave clouds crash over Boston area
Radical Kelvin-Helmholtz wave clouds in the Rockies
Pic of the week: Remarkable wave clouds paint the sky over Utah
Pic of the week: Surf’s up for snow lovers, incomparable Kelvin-Helmholtz clouds in Breckenridge
Shark fins in the sky: Awesome Kelvin-Helmholtz clouds from the Galapagos
Jason Samenow Jason Samenow is The Washington Post’s weather editor and Capital Weather Gang’s chief meteorologist. He earned a master’s degree in atmospheric science and spent 10 years as a climate change science analyst for the U.S. government. He holds the Digital Seal of Approval from the National Weather Association. Follow 2019 Heat Tracker 7 90-degree days so far Average Year-To-Date 6 Yearly Average 36 Record Most 67 (1980,2010) Record Fewest 7 (1886,1905) Last Year 45 Tweets by @capitalweather Subscriber sign in We noticed you’re blocking ads! Keep supporting great journalism by turning off your ad blocker. Or purchase a subscription for unlimited access to real news you can count on. Try 1 month for $1 Unblock ads Questions about why you are seeing this? Contact us
LINK ORIGINAL: Washington Post