Thursday, January 3, 2013

Definitions of the Many Types of Snow

Lately I've been hearing weather reporters speak of "snow showers". To me, a shower means rain, not snow. So I looked up online the different types of snow, as meteorologists talk about it.

Snow comes in a wide variety of forms -- snowfall, snow flurries, thunder-snow, snow showers, snow banners, snow squalls, snow blizzards, snow spouts, snow garlands, snow grains, snow rollers, lake-effect snow, snow hurricanes, and snow storms.

* The term snow storm can describe a heavy snowfall, while a blizzard involves snow and wind, obscuring visibility. Snow shower is a term for an intermittent snowfall, while flurry is used for very light, brief snowfalls. -- Wikipedia

* Snow Roller = The product of moist, cohesive snow that when initiated by wind rolls across the landscape, gathering snow until it can no longer move. It is shaped like a rolled sleeping bag, some reaching four feet across and seven feet in diameter. --

* Snow Banner = A plume of snow blown off a mountain crest, resembling smoke blowing from a volcano. --

* Snow Garland = Snow appearing as a beautiful long thick rope draped on trees, fences and other objects. Formed by the surface tension of thin films of water bonding individual snow crystals. --

* Snow Grains = Frozen precipitation in the form of very small, white, opaque grains of ice. The solid equivalent of drizzle. It is reported as "SG" in an observation and on the METAR. -- Weather. com

* Snow Spout (Snow Devil) = A small, rotating wind that picks up loose snow instead of dirt (like a dust devil) or water (like a waterspout). Formed mechanically by the convergence of local air currents. --

* Snow Squall = a heavy snow shower accompanied by strong winds. -- Ask Yahoo

* Snow Pellets (Soft Hail) = Frozen precipitation in the form of white, round or conical opaque grains of ice. Their diameter ranges from 0.08 to 0.2 inch (2 to 5 mm). They are easily crushed and generally break up after rebounding from a hard surface, unlike hail. Sometimes it is called small or soft hail. It is reported as "GS" in an observation and on the METAR. --

* Snow Shower = Intermittent snow falling from a convective cloud. --

* Snow Shower: short duration of light to moderate snowfall. Snow showers are characterized by their sudden beginnings and endings -- they're finite. They usually leave snow on the ground, but not always. Also, snow showers come from cumuliform clouds, as opposed to stratiform clouds. -- Ask Yahoo

* Snow Shower = snow system leading to an accumulation of snow between 1 to 3 inches. A snow shower brings more snow than a flurry, but less than a snow storm or a blizzard. - Wordnik

* Thunder-snow = Thundersnow, also known as a winter thunderstorm or a thunder snowstorm, is an extremely rare kind of thunderstorm with snow falling as the primary precipitation instead of rain. It typically falls in regions of strong upward motion within the cold sector of an extratropical cyclone. Thermodynamically, it is not different from any other type of thunderstorms but the top of the cumulonimbus are usually quite low. As well as snow, graupel, or more rarely hail also commonly falls. -- Wikipedia

* Lake-effect Snow = Snow produced during cooler atmospheric conditions when cold winds move across long expanses of warmer lake water, providing energy and picking up water vapor, which freezes and is deposited on the leeward shores. The same effect over bodies of salt water also occurs (e.g. ocean-effect snow, bay-effect snow). The effect is enhanced when the moving air mass is uplifted by the orographic influence of higher elevations on the downwind shores. This uplifting can produce narrow but very intense bands of precipitation, which deposit at a rate of many inches of snow each hour, often resulting in copious snowfall totals. The areas affected by lake-effect snow are called snowbelts. -- Wikipedia

* Snow Hurricane (Snowicane) = A hurricane that brings large amounts of snow, instead of rain.

Here are two bonus precipitation definitions that are not quite "snow":

* Frozen Dew = When liquid dew changes into tiny beads of ice. The change occurs after dew formation and then the temperature falls below freezing. -- National Weather Center

* Sea Smoke (Arctic Steam Fog) = a cloud over the sea, which could otherwise be called fog, and is usually formed when very cold air moves over warmer water. The physics are in principle similar to lake-effect snow. -- Wikipedia

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