13 Weather Terms You’ll Need to Know in 2020
Do you know a derecho from a Chinook wind? We're here to explain the difference between these two—and other wild forms of weather.
Does it seem like every new day brings news of some terrifyingly named storm that’s expected to unleash all manner of snow, rain, ice, and wind on the populace? Here’s a little primer on some of the most common in various regions throughout the country. These are the weather myths you need to stop believing.
A phenomenon not unlike your average thunderstorm, thundersnow produces snow instead of rain with its accompaniment of lightning and thunder. As Mental Floss explains, warm air rising quickly into the colder air above it—known as convection—occurs frequently over large lakes such as Ontario and Eerie and creates a storm forceful enough to make thunder. A fast-developing low-pressure system kicked up by a process called “forcing” can also produce thundersnow during blizzards and nor’easters (see below). Unlike a typical thunderstorm, however, thundersnow is a pretty quiet affair, since the fluffy white precipitation absorbs and muffles the cracking bursts of thunder. To be on the safe side, however, you should still avoid doing these 13 things during a thunderstorm.
Bombogenesis and bomb cyclone
Bombogenesis (also known as cyclogenesis) is a common winter occurrence that happens, according to the National Ocean Service, in mid-latitudes of the globe. It basically starts out as a regular cyclone that intensifies fast and furious, with a low-pressure system—defined as a region where sea-level atmospheric pressure is lower than the pressure surrounding it, and which creates precipitation as it rises—that drops intensely in a 24 hour period. It’s an explosive event that turns the storm into what’s known as a bomb cyclone. Even light snow can be as dangerous as heavy snow, though.
Downburst, macroburst, and microburst
As Weather.com explains it, a downburst is a strong wind that’s usually associated with the forceful, backward curling downdraft that occurs during a severe thunderstorm. It causes a straight and powerful line of wind that can cause damage over an area that’s between 1 and 250 miles wide. A “microburst” is a kind of downburst that happens on the smaller side of that equation—under 2.5 miles—producing winds that gust up to 160 miles an hour but that last only a brief five minutes. “Macrobursts” are at the opposite end of the spectrum, spanning more than 2.5 miles, with tornado-speed winds lasting as long as an hour. Find out the scientific reason why howling winds are so spooky.
Freezing drizzle and rain happen when warm air falls through cold air to create super-cooled precipitation. This all might start out gentle enough but there’s always the chance, if conditions are right, that this can turn into a full-fledged ice storm, a phenomenon known for its potential to cause extreme damage: super-slick roads that can lead to severe accidents, in addition to trees and power lines felled by thick and sudden coatings of heavy ice. Common in the Midwest and Northeast, says the Midwestern Regional Climate Center, the strong winds that accompany an ice storm compound the damage it can incur. A 2006 ice storm that affected Missouri and Illinois resulted in a week-long power outage for 2.4 million people, during the already frigid month of December. One place you don’t want to be when an ice storm hits: driving in your car.
We all know the Arctic is brutally cold (for now). When some of its cold air escapes south from the counter-clockwise spin that normally keeps it in place, this causes unusually frigid temperatures in southerly places—a polar vortex. It affects the northeastern portion of the United States most of all, due to the west-east movement of the jet stream that blows the freezing air out of its usual Arctic Circle holding pattern. And although polar vortices have been recorded for generations, National Geographic reports that the conditions that cause them are on track to get less stable with climate change. That means expect more escaped freezing air as the decade progresses. You can make these 20 tiny, everyday changes now to help the environment.
We’ve got all sorts of picturesque names for a wide variety of snowstorms, and Alberta Clipper is one of them. A storm that blows in from in and around Alberta, Canada, from December through February, according to the Farmers Almanac, an Alberta Clipper is known for the speed—reminiscent of an agile, 19th-century clipper ship—at which it descends on southerly regions in the Rockies, bringing winds of up to 45 miles per hour. It’s also distinguished by its biting cold, and the quick drop in temperature—sometimes as much as 30 degrees in a mere few hours—that comes along with it. Find out 11 mind-blowing facts you never knew about snow, until now.
A Pineapple Express is an “atmospheric river” that is caused by water vapor that builds up in the mysterious Pacific Ocean around Hawaii, from strong winds blowing over warm water. They can be mild, bringing much-needed rain and snow to parched coastal regions of California and the rest of the West Coast. Or they can be severe, causing deluges of precipitation—up to 5 inches in a day, according to NOAA. An informal and un-technical term (as is Alberta Clipper, for that matter), a Pineapple Express may be wet—very, very wet—but mercifully, when it gets where it’s going, it does so without wind. Find out 14 more ocean mysteries scientists can’t explain.
Chinook Winds/snow eater
Similar to the Alberta Clipper, strong, quick-moving Chinook winds are common in the Rocky Mountains, says Live Science. They rise rapidly from warm air blowing over from the Pacific Ocean and gain speed—gusts can reach up to 80 miles per hour—and drop in temperature as they move. After dumping rain or snow onto the mountain peaks, they gust their way east, getting drier and warmer again as they depart. Despite their regional name, taken from the Chinook Nation that makes its home in the area, Chinook winds occur in other parts of the country and the world. They’re known as the Santa Ana winds in California, puelche in the Andes, föhn winds in the Alps, and afganet in Central Asia. Over the Rocky’s they’re also known as snow eaters. As pretty as freshly fallen snow can be, you’ll want to think twice before you eat it.
It’s a name that sounds good and dramatic. But as USA Today points out, an arctic blast is just a souped-up name for a major cold front. A cold front is basically just the forward portion of a mass of cold air that’s moving in your direction; forming on its edge can be heavy rain or snowstorms. While we wait for them to arrive we may experience a warm downpour but behind the front is much colder, drier weather. When it does, you’ll want to know these 14 winter survival tips from the coldest parts of the country.
NOAA’s Storm Prediction Center defines a derecho as a long-lasting, destructive wind storm, like a tornado moving in a straight line rather than a swirl, that’s accompanied by quickly advancing thunderstorms that are variously referred to by a whole range of descriptive weather names: squall line, bow echo, or a quasi-linear convective system. A derecho’s winds gust at speeds of at least 58 miles per hour and its damage extends for 240 miles or more. You might be able to tell one is coming—and to prepare for it by seeking sturdy indoor shelter—by the appearance of very dark, somewhat terrifying looking “shelf” clouds. Find out the three things you must do to survive a tornado.
True to its name, a Nor’easter is a storm that’s common in the Northeastern part of the United States. While it develops at latitudes between Georgia and New Jersey, according to NOAA, it gusts up and gains maximum intensity in New England and Canada’s Maritime Provinces. You can tell a Nor’easter—just as you can a regular old hurricane—by its heavy rain or snow, its gale-force winds, extremely rough seas, and flooding. Although it can happen at any time of year, it’s at its strongest and most damaging between the months of September and April. Melting glaciers are predicted to intensify these kinds of storms, and make them more frequent.
Flood stage, crest, and rise
These are terms that are applicable to rivers that are rising due to storm activity, especially in southern, low-lying regions of the States. “Flood stage” is not so much a weather term as it is an indication that the water level of a river is high enough to cause economic hardship, according to the Suwanee River Water Management District—whether or not it actually overruns a riverbank. A “crest” is the highest point that a rising river reaches at its absolute peak. And “rise” is the word forecasters use when they aren’t sure what the crest will be—as in, we expect the river to rise to this particular height, but its crest could actually be higher. A devastating 1989 flood is one of the unbelievable natural disasters you never knew occurred in the United States.
Sudden, intense storms that feature massive amounts of rain can lead to flash flooding. As NOAA points out, small streams and creeks are usually extremely susceptible to this kind of furious overflow of water, sometimes rising several feet in just minutes flat. An ice jam in a river or other waterway can also lead to a flash flood; a flash (or any kind of) flood that occurs in a city is known as an urban flood, caused when poor drainage thanks to the non-absorptive abilities of pavement, causes severely flooded roadways and underpasses. Read on to find out what survivors of natural disasters wish they had done differently.