Wild, Wild Weather: Extreme-Weather Terms We Learned in 2021

Photo Courtesy: [Frederic J. Brown/Getty Images]

Wild, Wild Weather: Extreme-Weather Terms We Learned in 2021

The year 2021 will be forever defined as the time when the global community pushed back against an unparalleled pandemic. As many of us began stepping out into the world again, however, we found ourselves bombarded with extreme weather events. Blistering heat, subzero temperatures, wind, wildfires and other climate anomalies occurred while we continued masking up and getting vaccinated. And, while many of us were only beginning to process the effects of the pandemic, we were suddenly forced to confront severe weather events and their consequences.

When weather events become as unexpectedly extreme as they did in 2021, people need to create and spread new terms that describe them. Language is an important yet underrated tool for survival. Being on the right page about what the weather is or will be in a place can be a matter of life and death. As Earth’s climate continues to change and develop, our vocabularies will expand to describe new extreme weather events — and more of these words will become part of everyday lingo for many people. Terms like “thundersnow” and “bomb cyclone” are already entering popular usage, but they can seem intimidating and confusing. To better understand some of these extreme weather terms, we’re taking a closer look into those we’ve started seeing more often in 2021.  

Atmospheric River

Photo Courtesy: [NASA Earth Observatory, Public domain, via Wikimedia Commons]

You may have heard this term referred to as a “tropical plume,” “tropical connection,” “moisture plume,” “water vapor surge” or “cloud band” —  and these names all effectively describe what this weather event is. Atmospheric rivers start in the tropics. Picture a storm starting to build in those warm waters, much like a tropical storm, with humid air and water vapor rising up and forming clouds. Instead of moving to make landfall as many of them do, however, the water vapor stays in the tropics. A large, line-like mass then emerges from the water vapor and carries the vapor across different weather fronts. The mass of air in the atmosphere looks like a lake and river from above.  


These water vapor masses often bring heavy precipitation that results in flooding and landslides in affected areas. However, the moisture isn’t always damaging. In 2021, atmospheric rivers brought historic winds and rain to Northern California. While the state has experienced flooding and property damage due the effects of atmospheric rivers, it was also in dire need of rain. Precipitation from October 2021’s storm extinguished remaining wildfires and raised water reservoir levels.


Photo Courtesy: [Serrnovik/iStock Images]

Thundersnow is the official term for thunder that occurs during a snowstorm or a thunderstorm that releases snow instead of rain as its main form of precipitation. The U.S. experienced thundersnow at the beginning and the end of 2021. The year brought new developments to scientists’ understanding of thundersnow by way of the geostationary lightning mapper (GLM), a tool that helps them detect and map lightning around the world.


Thundersnow occurs most commonly in the Great Lakes region through lake effect snow. How exactly does thundersnow occur? Essentially, the cold air in a snowstorm can sometimes be vacuumed upwards in a process called vertical mixing, allowing what little warm air is left to create thunder on a snowstorm’s surface.

Bomb Cyclone

Photo Courtesy: [Justin Sullivan/Staff/Getty Images]

Formally known as “explosive cyclogenesis,” a bomb cyclone describes a storm — a low-pressure system, scientifically speaking — with sudden upticks in strength. These can be caused by atmospheric rivers, like the bomb cyclone that hit the Pacific Northwest in October of 2021. Bomb cyclones can cause flooding, and their winds can reach speeds of 74 to 95 miles per hour rather quickly. This extreme weather burst can warrant evacuations, stay-home orders and other protective measures. Other terms for bomb cyclones you might hear from meteorologists include “weather bomb,” “explosive development,” “meteorological bomb” and “bombogenesis.”



Photo Courtesy: [Stocktrek Images/Getty Images]

While derecho translates to “right,” “correct” or “straight ahead” from Spanish to English, meteorologists see derecho as a fitting term for this weather event because it describes wind that’s strong yet straight. This contrasts with a tornado, in which wind moves in a circular motion. A derecho is a large, straight-winded and long-lasting thunderstorm that’s made up of a complex of smaller thunderstorms. This weather phenomenon typically happens during summer months in hot, humid areas that are mostly flat.


Summertime, for many, includes scattered showers that are sometimes accompanied by thunder. These smaller storms may not amount to much and are sometimes even welcome amidst summer heat. But they can also be destructive. In 2021, Wisconsin and parts of Michigan felt the force of a derecho. Wind gusts hit 90 miles per hour, and 37 tornadoes were reported by the National Weather Service. Derechos also affect states in the Ohio River valley.

Flash Drought 

Photo Courtesy: [Thinnapat Porbootdee/Getty Images]

According to the National Weather Service, “Flash drought is simply the rapid onset or intensification of drought. It is set in motion by lower-than-normal rates of precipitation, accompanied by abnormally high temperatures, winds, and radiation.” This issue is affecting many of the U.S.’s western states and is often connected to the greater conversation surrounding climate change.


Flash droughts can lead to massive wildfires, which have unfortunately become an annual occurrence in states like California, Colorado and Oregon. Droughts can also destroy animal habitats and cause famine, among other negative effects. Flash drought can be a difficult weather event to deal with, but talking about them and spreading awareness can be the first step in combating their effects.

Ice Storm

Photo Courtesy: [Mbbirdy/iStock Images]

You’ll want to bundle up for this one — an ice storm features freezing rain, not regular rain, as its primary form of precipitation. Freezing rain is sometimes associated with hail or sleet, but those are actually different types of precipitation. Freezing rain is like normal rain, but it begins the freezing process on its way down. Hail and sleet are both produced higher up in the atmosphere; freezing rain forms much closer to people’s heads.


Ice storms are known to happen almost every year, but February of 2021 was full of them. Winter Storm Uri impacted Canada and Mexico in addition to the U.S. Texas, a state not known for snow or ice, felt unprecedented impacts from this winter storm. More than a half-inch of ice accumulated on the ground in places that weren’t used to seeing frost. The storm left thousands of Texans without power, prompting many people to question whether U.S. infrastructure is prepared for climate disasters.

Heat Dome

A Portland cooling center reaches capacity during an unprecedented heat dome. Photo Courtesy: [Nathan Howard/Stringer/Getty Images]

What happens when high pressure pushes down on summer air? It creates a “dome” that traps heat in the air that humans breathe and feel. This extreme weather moment happened in the summer of 2021 and created record-breaking heat in different parts of North America. According to AccuWeather, Portland, Oregon, smashed its one-day heat record of 100° F with a high of 116° F. North of the U.S., Canada’s all-time heat record rose to 121° F.


Sudden changes in heat can lead to heatstroke, dehydration and other heat-related health complications. There are also potential long-term effects of a heat dome. The change in the air could negatively affect breathing, cause skin issues, alter animal ecosystems and cause other issues. NOAA’s National Ocean Service notes that changing oceanic temperatures are a strong factor in the creation of a heat dome — yet another issue related to climate change.

Polar Vortex

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Picture two hurricanes constantly building strength on each of Earth’s poles. That’s essentially what the polar vortexes are. Each of Earth’s poles has its own mass of air that develops strength during each pole’s winter. In the Northern Hemisphere, winter months have seen colder temperatures and progressively more severe winter weather alerts. While not an official term, many refer to an “arctic blast” whenever the polar vortex acts up. The polar vortex can create weather effects like thundersnow, extreme low temperatures and cold waves, blizzards and ice winds.  

We don’t know what words might soon be added to our weather lexicon or which older words might resurface. Words, like weather, often can’t be predicted. But as they emerge, they become key tools we use to better understand our world and the weather conditions that affect our lives.