Dust Devil — The Farmers’ Almanac glossary defines it as “a rapidly rotating column of air that swirls dust, debris and sand to great heights, and superficially resembles a small tornado. Caused by superheated air above a sun-baked ground that rises into cooler air… Sometimes also called a whirling dervish.” Other names for this phenomenon include “dancing devil” and “sun devil.” They tend to be small–3 feet in diameter or less–although there have been recorded instances of dust devils becoming over 300 feet wide. They are similar in form to a waterspout, which forms over a body of water, and a snow devil, which is a whirling column of snow.
Green Flash — No it’s not a superhero, although it sounds like one. Green flashes or green rays are green colorations that occur shortly after sunset or before sunrise.
A Mackerel Sky is a “formation of cirrocumulus or altocumulus clouds that look like the pattern of scales on a mackerel’s back.” Sailors used to say: “Mackerel sky, mackerel sky. Never long wet and never long dry,” since its appearance signaled stormy weather to come. In some places it is also called a buttermilk sky.
Gully Washer — Is an extremely heavy downpour that causes flash flooding when ditches (or gullies) overflow.
Mare’s Tail — A formation of cirrus clouds that are wispy and stretch across the sky like a mare’s tail blowing in the wind. Weather lore about them says: “Mackerel scales and mare’s tails, make lofty ships carry low sails.”
Knot — A knot measures a unit of speed of one nautical mile per hour (equal to about 1.151 mph). The unit got its name from sailors who used to measure speed letting out a rope with knots tied in it. They would count the number of knots let out in 30 seconds to tell how fast they were sailing.
Indian Summer — Is “a period of abnormally mild weather, occurring in the late autumn or early winter, usually after the first frost.” The origin of the term is uncertain, but a likely one suggests that early colonists used the word “Indian” to mean “false,” thus a an Indian Summer would be a false summer.
Snow Eater — A term used to describe warm dry wind that blows over a snowy terrain and melts the snow. Usually used in the Rockies.
Check out the Farmers’ Almanac Weather Glossary for more unusual weather terms!
— Written by Farmers’ Almanac Freelancer Kristen Hewitt.