Derecho, Firenado, Gustnado: 26 Weather Words To Know, From A-Z

ACROSS AMERICA — The arrival of spring can turn the weather dictionary into a veritable compendium of fear as we use words associated with extreme weather events.

A term we don’t hear often — derecho — returned to our lexicon last summer after what was an unusually wide, long-lasting storm with hurricane-force winds tore through a half-dozen states, joining hurricanes and tornadoes as terrifying windstorms.

There are other unusual words that sound too frightening to be real — and, oh hell, no, “Sharknado” isn’t among them. But before we dip into the real pool of dread that may lie ahead, here are three terms you should familiarize yourself with. These alerts are issued for weather events such as thunderstorms, windstorms, tornadoes, flooding and, soon, hurricanes.

From the National Weather Service:

• Warning: A warning is issued while hazardous weather is occurring, imminent or likely, and means weather conditions pose a threat to life or property.
• Advisory: An advisory is also issued while hazardous weather is occurring, imminent or likely, but for conditions that are less serious than those prompting a warning; these events can still cause significant inconvenience if caution isn’t exercised, and could lead to situations that may threaten life or property.
• Watch: A watch is issued when the risk of severe weather is heightened, but the exact timing and location of the event hasn’t been determined; watches are intended to give people time to prepare for hazardous weather.

Now, from A to Z, here are 26 weather words and phrases to know:

A

Atmospheric river: Known as “rivers in the sky,” atmospheric rivers are relatively long, narrow and always moving columns of vapor roughly equivalent to the average flow of water of the Mississippi River, according to the National Oceanic and Atmospheric Administration. When they reach landfall, they unleash a torrent of rainfall or snow.

B

Bombogenesis: The term popularized by meteorologists describes a mid-latitude cyclone that rapidly intensifies, dropping at least 24 millibars (the standard used by the National Weather Service to measure atmospheric pressure) in 24 hours. This often happens when warm and cold air masses collide. This can create what’s called a “bomb cyclone.”

C

Cyclone: Cyclones, hurricanes and typhoons are essentially the same thing; what they’re called depends on where they occur. Hurricanes are the tropical storms that form over the North Atlantic and Northeast Pacific oceans; cyclones form over the South Pacific and Indian Ocean. Typhoons form over the Northwest Pacific Ocean.

D

Derecho: The term derecho was coined in 1888 by University of Iowa physics Gustvus Hinrichs, who wanted to distinguish between these widespread, long-lasting destructive straight-line winds and tornadoes. The term was resurrected in 2012 when a derecho left a wide swatch of damage from Ohio to the mid-Atlantic coast. Last August, a derecho traveled 770 miles in 14 hours, leaving destruction in a half dozen Midwest states.

E

El Niño & La Niña: They are the warm and cool phases, respectively, of a recurring climate pattern over the tropical Pacific Ocean that together are known as El Niño-Southern Oscillation that swings back and forth every three to seven years; among the effects in the United States, El Niño can cause more rain than usual, while La Niña can lead to drier-than-usual conditions across the Southwest.

F

Firenado: The National Weather Service issued the first-ever fire tornado warning during the 2020 wildfire season, though the term had been used at least since 2018 to describe the fire whirl that occurs when very intense heat rises from the fire, is enveloped by the surrounding air and creates a spinning column of air; it’s also called a fire devil or fire tornado.

G

Gustnado: This is a small, weak and short-lived tornado that occurs along the gust front of a thunderstorm; a gustnado may look like a debris cloud or dust whirl near the ground.

H

Haboob: These intense sand and dust storms, with wind speeds over 40 mph, occur globally, despite an Arabic name that means “blasting”; in North America, it is sometimes used interchangeably with “dust storm.”

I

Iridescent clouds: The brilliant patches of green or pink that are sometimes seen near the edges of high- or medium-level clouds are associated with thunderstorms and occur the same way rainbows do — in fact, they’re sometimes called fire rainbows or rainbow clouds.

J

Jet stream: These are narrow bands of strong winds in the upper atmosphere, generally blowing from west to east, that steer fronts and low-pressure systems.

K

Knuckles: A slang term used by storm spotters to describe a thunderstorm anvil’s lumpy protrusions. Found on the edges and sometimes on the underside of the black-sheared anvil, they indicate a very strong updraft and rapid expansion of the storm.

L

Lenticular clouds: Stationary clouds that form mainly in the troposphere, the lowest region of the atmosphere, they can look like UFOs or flying saucers and are formed when stable, moist air flowing over a mountain or mountain range (though they also form in non-mountainous places) and swoops downward. Sometimes called “standing wave clouds,” they are a signal of atmospheric instability.

M

Microburst: Also called a macroburst, this is a small, concentrated downburst — that is, strong winds on or near the ground that cause damage similar to a strong tornado and typically associated with thunderstorms — that typically affects an area no larger than 2.5 miles wide and typically lasts only 5 minutes, though some have lasted five times that long.

N

Northern lights: The colorful aurora borealis light shows sometimes dip down into the central United States, but are primarily confined to Alaska and other parts of high latitude states; they occur after solar storms when Earth’s magnetic field interacts with charged particles from the sun.

O

Obscuration: Whether mist, fog, smoke, volcanic ash, dust, sand or haze, an obscuration is any phenomenon in the atmosphere, other than rain or snow, that reduces visibility.

P

Petrichor: The earthy scent that remains after a storm has passed, usually after a period of dry weather; as the word petrichor was coined in 1964, it described the airborne molecules from decomposing plant and animal matter that settled on mineral and clay surfaces, but is now used to describe the smell of rain.

Q

Quantitative precipitation forecast: Often shortened as QPF, it is meteorologists’ best estimate of the chance that a given area will receive an amount or rain that exceeds a certain threshold value, according to the National Weather Service.

R

Rainbow: Among nature’s most glorious displays, rainbows occur when sunlight and rain droplets intersect; sunlight enters many droplets of water at once, reflecting from the inside of the droplet and separating component wavelengths, or colors, and creates rainbows as it exits.

S

Swullocking: Used primarily in the southeastern United States, it is used to describe a hot, sweltering and sultry day.

T

Tornado: Often occurring in the spring and summer months (though occasionally at other times), these narrow, violently rotating columns of air extending from a thunderstorm to the ground are among the most violent of all atmospheric storms.

U

Upper air: What happens up there dictates what happens down here; Earth’s atmosphere above 5,000 feet is the source of the weather we experience at the ground level, whether rain and drought, wind and calm, heat and cold; meteorologists look at what’s happening in the upper air before forecasting what will happen on the ground.

V

Virga: Streaks or wisps or rain that fall from a cloud but evaporate before they reach the ground; shafts of viirga may precede a microburst.

W

Waterspout: They may be a tornadic or fair weather waterspouts; the former is a tornado that forms over water or moves from land to water associated with severe thunderstorms and having the same characteristics as a land tornado, while fair weather waterspouts usually form along the dark, flat base of a line of developing cumulus clouds that move very little and are not associated with thunderstorms.

X

X-rays: A type of electromagnetic radiation with wavelengths between gamma rays and ultraviolet radiation; they’re nothing to be too concerned about: essentially all X-rays from space are absorbed in Earth’s upper atmosphere.

Y

Young ice: One of the stages of sea ice development. When ice forms on the sea, it starts out as “new ice,” evolving into “nilas” as it thickens and hardens and finally into “young ice”; all three stages of ice development are collectively known as “first year ice,” and if it survives a second year, it’s known as “old ice” or “multiyear ice.”

Z

Zigzag lightning: A flow of electrons about a thousand times stronger than the electric current in our houses, lightning takes the most direct path to the ground; sometimes it’s in a straight line, but fluctuations in temperature, humidity and dust particles in the air can result in a zigzag pattern in lightning.

---