What are mammatus clouds? Stunning photos here

Mammatus clouds may seem ominous. But they have a magnificent beauty of their own.

Three images of gray clouds with many downward bulges.

View larger at EarthSky Community Photos. | Adelina Bathorja in Tirane, Albania, captured these clouds on May 14, 2020. Adelina wrote: “For the first time ever I see mammatus clouds. Just, wow! It was a spectacular view of cellular and jellyfish patterns.”

Mammatus clouds are pouch-like protrusions hanging from the undersides of clouds, usually thunderstorm anvil clouds but other types of clouds as well. Composed primarily of ice, these cloud pouches can extend hundreds of miles in any direction, remaining visible in your sky for perhaps 10 or 15 minutes at a time.

People associate them with severe weather, and it’s true they can appear around, before or after a storm. Contrary to myth, they don’t continue extending downward to form tornados, but they are interesting in part because they’re formed by sinking air. Most clouds are formed by rising air. Mammatus clouds can appear ominous. But, in a way that’s so common in nature, their dangerous aspect goes hand in hand with a magnificent beauty.

Rows on rows of downward bulging clouds extending nearly to the horizon.

View at EarthSky Community Photos. | Marlane Burns captured this image on May 15, 2020, near Robert Lee, Texas. She said: “Mammatus clouds preceding a northern thunderstorm that came out of nowhere! The wind blew the flies away and the rain settled the dust!”

Four images of clouds with multiple rounded downward bulges in orange dawn light.

View at EarthSky Community Photos. | Peter Lowenstein captured these spectacular mammatus clouds in Mutare, Zimbabwe, on March 23, 2020. He wrote: “I took an early morning walk up to the Murambi High Level Water Tanks in the hope of catching a glimpse of the very thin old moon rising. Instead there was a surprise appearance of mammatus clouds on the underside of a sunrise-illuminated band of altostratus cloud above.”

Clouds with multiple glowing white rounded downward bulges.

Stephanie Tilden Dorr in Wichita, Kansas, caught these clouds in June 2018. She wrote: “Mammatus clouds appearing exactly one hour after a hailstorm passed over. Twenty-five years in Kansas and I’ve only seen mammatus clouds this vivid one other time, years ago. So exciting!”

Mammatus clouds in New Jersey, lit by the sun from beneath.

Mammatus clouds over New Jersey, via Phil Chillemi.

Huge slightly pinkish gray downward cloud bulges over treetops.

Mammatus clouds via Andrew Hill in Gloucestershire, U.K.

Rows and rows of downward bulges lit from below, all red-orange in sunset light.

Crystal Kolb caught these mammatus clouds from Essex, Maryland – near Baltimore – after a bad storm.

Irregular gray bulges with small plane in the air showing their size.

Mammatus clouds at sunset from Andrew Ashton in Nampa, Idaho.

Patch of mammatus clouds on underside of big storm with two streaks of sky-to-sky lightning.

Josh Blash caught these mammatus clouds illuminated by lightning over Rye, New Hampshire.

Blue-appearing large downward bulging clouds.

From Lorrie Wy, who wrote in May 2014, “Bubbly clouds over central Alberta, approximately 9:20 p.m. Temp approximately plus 12. Winds cold and light from northwest. These clouds just rolled right over.”

Pointy downward bulges side-lit by lowering sun.

Berit Roaldseth in Trondheim, Norway, saw these mammatus clouds after an April rain shower.

Streak of clouds with downward bulges starting to dissipate.

Mammatus clouds over Fayetteville, Arkansas, just before sunset. Image via Mike Price.

Dark bulging downward clouds lit from below against red streak of sunset.

Mammatus clouds over Fort Worth, Texas, in May 2013 – the day a tornado struck near Oklahoma City. Photo via Sundog Art Photography.

Spectacularly orange and yellow lit mammatus clouds covering the sky.

Pam Rice Phillips caught the same mammatus clouds as in the image above, on May 20, 2013, the day a tornado struck Moore, Oklahoma. She was in Granbury, Texas, which is southwest of Fort Worth.

Low bulging clouds over the sea.

Mammatus clouds over Tynemouth, England, via Colin Cooper.

Fuzzy-looking mammatus bulges in purple sky.

Mammatus clouds over Salt Lake City, Utah, from Shanna Dennis.

Swirling, streaming gray clouds with many downward bulges.

Mammatus clouds over Denver in 2012 via Larry Sessions.

Clouds bulging downward over tall sunlit mountain feature.

Mammatus clouds over Half Dome in Yosemite National Park in June 2013 by Kristal Leonard.

Bottom line: A spectacular collection of photos of mammatus clouds.

Deborah Byrd