The leaves are altering color, and there’s a chill within the air; autumn is right here, which suggests winter is simply across the nook. Just just like the altering seasons, the varieties of climate and phrases we use additionally start to alter—shifting away from thunderstorms and transferring towards snowstorms.
However, these colder months aren’t simply all about fluffy, blowing snow; there are a slew of meteorological phrases and phrases used to explain the whole lot from the kind of ice we see type to the kind of storm that’s brewing over the continent.
To these within the meteorological area, these phrases and phrases are about as clear as ice, however to others they might not even sound like actual phrases.
With that mentioned, listed below are just some of the various phrases chances are you’ll hear in your fall and winter forecasts:
Frazil ice
You might have encountered frazil ice earlier than, pondering it was one thing else.
Frazil ice comes from the formation of ice crystals in flowing, supercooled water. Since the water is flowing, the ice crystals can’t type one strong sheet, so as a substitute it turns into extra ‘slush-like’, with the ice crystals oriented in random instructions.
WATCH: This stream disappears as you watch and frigid climate is accountable
Don’t get too frazzled, although; there is a crucial distinction between frazil ice and slush.
Slush types from snow and ice being warmed to simply above freezing—to the purpose the place it begins to soften, however not utterly. Essentially, it’s the inverse of frazil ice in that it’s ice crystals slowly returning to a liquid state, whereas frazil ice is fashioned from water crystallization into ice.
Frazil ice can grow to be problematic for municipalities when temperatures drop as it may possibly type inside water pipes and mains, inflicting them to interrupt.
Additionally, frazil ice in rivers can contribute to flooding by accumulating and blocking water flow.
Frost quake
Imagine this: after a gentle and moist winter, out of the blue an Arctic vortex descends over your area and freezes the whole lot in a single day. You get up within the night time to a growth, and your home begins to shake barely, however you’re not in a seismically lively space, so what triggered this mysterious quake?
That could be a frost quake, often known as an ice quake or cryoseism. It’s essential to notice {that a} frost quake will not be the identical as an earthquake, as it isn’t the results of tectonic activity.
A frost quake is seismic exercise ensuing from the sudden freezing of water deep within the saturated floor.
Water expands when it freezes, and when it freezes deep within the saturated floor, the bottom will start to crack and out of the blue burst from the sudden enlargement.
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Graupel
Graupel is one other title for snow pellets. Smaller than hail however denser than snow, graupel is fashioned from ice crystals excessive in a cloud falling and colliding with supercooled water, freezing into small spheres that fall to the bottom.
While you might have heard graupel known as ‘delicate hail’, it’s, the truth is, not hail. For starters, hailstones have to be at the least 5 mm in diameter to be thought of hailstones. Hail can be fashioned from sturdy updrafts in highly effective storms, which elevate water droplets to the freezing stage in a storm cloud till it turns into so heavy that it falls to the earth.
Graupel is way smaller than hail, being about the identical measurement as a snowflake, and isn’t fashioned by means of updrafts.
These small pellets have additionally been known as ‘tapioca snow’ attributable to their tapioca pudding-like look after they accumulate!
WATCH: What is graupel? We break down this typically confused precipitation sort
Thundersnow
While summer season will be the season for thunderstorms, it’s attainable to see the odd storm or two develop within the fall and winter as properly.
When this occurs, we see the precipitation fall as snow, as is predicted within the winter, however lightning out of the blue lights up the sky and a rumble of thunder stirs the air.
Thundersnow occurs when a mass of unstable, frigid air sits above a rising mass of comparatively hotter air, such because the air over giant, ice-free our bodies of water, or in among the strongest winter storms. While the air contained in the cloud and on the floor are nonetheless chilly sufficient for snow improvement, the distinction in temperatures between the higher and floor ranges is nice sufficient to gas lightning improvement and, thus, thunder. Thundersnow tends to happen within the space of a storm the place you could have the best instability within the storm.
Lightning from thundersnow will seem brighter within the sky as a result of gentle being mirrored off the ice crystals and snow within the clouds. Thunder from thundersnow will nonetheless be loud if you happen to’re close to the lightning, however the sound gained’t carry far distances prefer it does in the summertime as a result of the snow acts as a sound insulator.
WATCH: Rare thundersnow caught on digital camera in Oshawa, Ontario
Weather bomb
The phrase ‘weather bomb’ might sound made up and, fairly frankly, exaggerated, however we are able to guarantee you it is rather actual and ought to be taken severely.
The phrase comes from the time period ‘bombogenesis’, which is when the centre of a low-pressure system rapidly decreases in pressure over a brief period of time. If a system’s minimal strain falls by at the least 24 mb in beneath 24-hours, it’s thought of a climate bomb or ‘bomb cyclone’.
We see this occur extra typically within the colder months as a result of contrasting conflict between chilly continental air and heat tropical air alongside North America’s coasts. The conflict in temperatures fuels giant and highly effective storms to develop, most frequently off the East Coast as Nor’easters.
The fast drop in strain with these methods additionally leads to a fast improve within the storm’s depth, posing a larger risk to these within the storm’s path. Precipitation and winds can quickly change in depth, turning into harmful in mere hours.
