ENVIRONMENT

Technically called “lenticular clouds,” the weird phenomenon has a simple explanation. (Nat Geo News)

Use our resources to learn more about clouds.

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit.

Discussion Ideas

• What are lenticular clouds?
  • Lenticular clouds form as strong winds blow across complex terrain, causing water vapor in the air mass to condense into a lens-shaped structure. Lenticulars are stationary clouds that are usually good indicators of turbulence in the atmosphere.

• According to Nat Geo News, lenticular clouds form “when strong, moist winds blow over rough terrain, such as mountains or valleys.” Lenticular clouds were recently documented over the Cape Town, South Africa. What conditions allow for lenticular clouds around Cape Town? (In other words: What is the source of the strong, moist winds? What is the rough terrain?)
  • Strong winds blow over Cape Town from the South Atlantic Ocean.
  • Cape Town is surrounded by four mountains: Signal Hill, Lion’s Head, Table Mountain, and Devil’s Peak.

• Where else do you think weather and landscape might contribute to the formation of lenticular clouds?
  • Click through the gallery to find out!

Strong winds from the North Atlantic blow over Madiera, a rocky Portuguese island off the coast of Morocco. Photograph by Karlheinz Essl, courtesy Wikimedia. CC-BY-SA-4.0

Strong winds from the North Atlantic and Arctic can blow through the Adirondacks, a mountain range in upstate New York. Photograph by Michael Melford, National Geographic

Winds from the North Pacific and the Sea of Japan blow over the Hida Mountains of central Honshu, Japan. Photograph by Alpsdake, courtesy Wikimedia. CC-BY-SA-3.0

Winds from the North Pacific and Arctic can blow through the Cascade mountains in Oregon. Photograph by John2165, courtesy Wikimedia. CC-BY-SA-3.0

Winds from the African Great Lakes can blow through the Virunga mountains and rain forests of Democratic Republic of Congo. Photograph by (WT-shared) Cai, courtesy Wikimedia. Public domain.

Strong winds from the South Atlantic can whip across South Georgia Island, a rocky British territory off the coast of Antarctica. Photograph by Lieutenant Elizabeth Crapo, NOAA Corps. CC-BY-2.0

Strong winds from the Arctic can blow across the Penny Ice Cap of Baffin Island, Nunavut, Canada. Photograph by NASA/John Sonntag

• The Cape Town lenticulars are described as “stratocumulus.” What does this word tell us about these clouds? Take a look at our glossary words for stratus and cumulus for some help.
  • Stratus or strato- describes the elevation of clouds in the atmosphere. Stratus clouds are usually about 2,000 meters (6,562 feet) above Earth.
  • Cumulus describes the clouds’ shapes. Cumulus clouds are generally large, with flat bottoms and fluffy tops.

• Why are lenticular clouds associated with UFOs?
  • Their appearance is similar to the classic bulging oval shape of a “flying saucer.” Learn more about the pursuit of unidentified flying objects here.

TEACHERS’ TOOLKIT

Nat Geo: “UFO Clouds” Are Real. Here’s How They Happen

Nat Geo: What is a cloud?

National Weather Service: Lenticular Clouds