Weird Weather: How to Tell a Williwaw from a Haboob

Weird Weather: How to Tell a Williwaw from a Haboob

Extreme weather is more common these days. We are used to hearing about unusually strong storms , tornadoes and even the polar Vortex ,. But atmospheric events can get much more bizarre–and so can the names we give them. These bizarre weather phenomena have fascinating names.

Atmospheric River/Pineapple Express

A 2019 atmospheric river drenches California with heavy rain and mountain snow.
A 2019 atmospheric river drenches California with heavy rain and mountain snow, triggering flash floods and mudslides. Credit: NOAA

A “river” of water vapor in the sky that can grow to 2,000 miles long, 500 miles wide and two miles deep. These rainstorms can be driven by strong winds from the midocean regions to the western coasts. The heaviest atmospheric rivers strike the U.S. and Canada–where they can carry vapor equivalent to 25 times the flow of the Mississippi River and can produce the biggest floods in a century. In 1861 one turned California’s Central Valley into an inland sea 300 miles long and 20 miles wide. If it comes from Hawaii, some forecasters call this an atmospheric river.

Bomb Cyclone/Bombogenesis

A man walks outside the Oculus transit hub in New York City during a winter “bomb cyclone” storm.
A man walks outside the Oculus transit hub in New York City during a winter “bomb cyclone” storm in January 2018. Credit: Gary Hershorn/Getty Images

A bomb cyclone is a rapidly growing storm that brings heavy rain and snow. It is generated by bombogenesis–when a storm’s barometric pressure plummets by at least 24 millibars in 24 hours, causing the system to “blow up” in strength. The nastiest nor’easters (storms that spin up along the U.S. East Coast and typically result in strong winds over the Northeast) are often caused by bombogenesis.


A dramatic derecho moves across eastern Montana.
A dramatic derecho across eastern Montana. Credit: John Sirlin/Alamy Stock Photo

A widespread, severe and long-lived windstorm that moves rapidly in a straight line, usually driven by thunderstorms. The term derecho–a Spanish word meaning “straight”–designates a storm with gusts of at least 58 miles per hour and “straight-line wind” damage that extends more than 240 miles [see “Straight-Line Wind/Downburst/Microburst” at bottom]. An August 2020 derecho that raced across Iowa reportedly damaged thousands of homes and millions of acres of corn and soybeans, representing a major fraction of the state’s cropland.

Firenado/Fire Whirl

A firenado rises out of intense flames at the Pine Gulch Fire.
A firenado rises out of intense flames at the Pine Gulch Fire near Grand Junction, Colo., in August 2020. Credit: USFS Photo/Alamy Stock Photo

A spinning vortex of hot air and gases, which rises quickly from an intense wildfire, can carry smoke, debris, and flames hundreds upon hundreds of feet into atmosphere. These whirls range from a few feet to 500 feet in diameter, and the largest ones can carry embers long distances.

Flash Drought

Flash drought parches the earth by the Maglova Aqueduct in Turkey.
Flash drought pries the earth by the Maglova Aqueduct, Turkey. Credit: HSNPhotography/Getty Images

The rapid onset of drought, triggered by low precipitation, abnormally high temperature, strong winds and searing sun. Flash droughts accelerate evapotranspiration–soil and plants giving up excessive moisture–which can ruin crops.


Liquid water droplets freeze onto the surface of a snow crystal.
Liquid droplets of water freeze on the surface of a crystal of snow. Graupel is the name given to a crystal that has been formed by freezing liquid water droplets onto a snow crystal’s surface. Credit: Science Source

There are hard hail pellets and soft snowflakes. Graupel, a type of soft hail, is in between. In uncommon atmospheric circumstances, very cold water droplets aloft freeze onto snowflakes and fall with them, hitting the ground with a squishy plop.


A haboob approaches the outskirts of Khartoum, the capital and largest city of Sudan.
A haboob approaches Khartoum’s outskirts, the capital and largest city in Sudan. Credit: Jordistock/Getty Images

In Arabic, this term refers to a strong, violent dust storm or the sandstorm. As more intense haboobs cut across the Middle East and northern Africa, media coverage has been extensive. Winds can drive dust at up to 60 mph, crippling transportation and infiltrating people’s lungs, even though these events often pass in less than an hour.

Pogonip/Ice Fog

Winter ice fog covers a river and birch grove.
Winter ice fog covers a river & birch grove. Credit: Azovsky/Getty Images

Fog is made of water vapor, yet sometimes ice particles can create the ephemeral mistWhen the air temperature is below freezing and relative humidity is greater than 100 percent–an infrequent combination–these ice crystals can form and hover to form a “pogonip,” or ice fog. Pogonips are most common in deep mountain valleys. The term is usually credited to the Shoshone peoples: it is said to be derived from the Shoshone word payinappih, which means “cloud.”

Saskatchewan Screamer/Alberta Clipper

A fast-moving Alberta clipper drops snow across the U.S. Upper Midwest and Northeast.
A fast-moving Alberta snow clipper drops snow across the U.S. Upper Midwest, Northeast. Credit: NASA images by Jeff Schmaltz/LANCE/EOSDIS Rapid Response

A fast-moving, low pressure weather system that forms when cold Arctic air descends into Canada’s province Saskatchewan and moist Pacific Ocean air simultaneously arrives to the west. The resultant collision creates howling winds that blow southeast towards the U.S. Great Lakes area, whipping up local whiteouts and blizzards even though snowfall totals are low. It’s called an Alberta clipper when a similar system begins further west in the province.

Siberian Express

People out in the cold in Times Square, New York City.
Bitterly cold temperatures delivered by a “Siberian Express” reach Times Square in New York City, setting record lows in many places along the way. Credit: Wang Lei/Xinhua/Alamy Live News

A surge of extremely cold, high-pressure air that forms over Siberia and travels across the North Pole to drop into Canada or the United States, causing temperatures to plummet. Sometimes, these systems move eastward and grip Japan.


People walk in Times Square during a blizzard.
People walk in Times Square during a blizzard in January 2016. Credit: Noam Galai/WireImage/Getty Images

The term “snowmageddon”, and its colorful synonyms, may be more popular than meteorology. The terms have become popular in the media, as they are used when snowstorms engulf an area that is usually not subject to snow. One famous case was the January 2016 blizzard that struck Washington, D.C., shutting down the city and the federal government for several days. Another “snowpocalypse” befell the city again in February 2010.


Hurricane Irene moving over the Bahamas in 2011.
Hurricane Irene moving over the Bahamas in 2011. Stormquakes were felt near Little Bahama Bank on the archipelago’s seafloor. Credit: NASA image courtesy of Jeff Schmaltz/MODIS Rapid Response Team, NASA GSFC

Some storms over the ocean, such as hurricanes, can cause very large waves to crash into the seafloor. Sometimes, this can cause vibrations similar to an earthquake on Earth’s surface. Although researchers only discovered the phenomenon a few years ago, by studying seismic records and storm tracks back in time, they found that thousands of stormquakes had occurred from 2006 to 2019 near the U.S. and Canadian coasts. Some were as strong as a magnitude 3.5 earthquake.

Straight-Line Wind/Downburst/Microburst

A microburst strikes in Bangkok, Thailand.
A microburst strikes in Bangkok, Thailand. Credit: Natapat Ariyamongkol/Getty Images

Strong thunderstorms can produce tornadoes but also powerful winds without rotation. These are known as “straight-line winds” and draw high-altitude air straight down. When it hits the ground, this “downburst” fans out in a straight line, with wind that can exceed 100 mph, causing dangerous conditions and property damage. A “microburst”, or a very localized downburst, is an example.


Snowstorm on Hawaii’s peaks.
A snowstorm that dumped snow on Hawaii’s peaks brought lightning and thunder as well. Credit: NASA Earth Observatory images by Jesse Allen, using Landsat data from the U.S. Geological Survey

This word is quite self-explanatory. It describes a thunder or lightning storm that produces snow instead of rain. It can be strange to stand in a snowy storm, given how strongly thunderstorms are associated with rain.


A williwaw blows in Terra Nova Bay, along the coast of Victoria Land, Antarctica.
A williwaw blows in Terra Nova Bay along the coast of Victoria Land (Antarctica). Credit: Andrew Peacock/Getty Images

A sudden, powerful gust of cold, dense, air that descends from mountaintops to the coast. This down blast can cause havoc on ships and cause severe flooding along the coast. Williwaws are most common at high latitudes such as the Aleutian Islands off Alaska or the Strait of Magellan near Chile’s southern tip. Gore Vidal’s first novel was Williwaw, which he wrote while stationed on a U.S. Army supply ship in the Aleutian Islands.



    Mark Fischetti is a senior editor at Scientific American. He cover

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