Snowsquall warning
Encyclopedia
Snowsquall warning is a bulletin issued by Environment Canada
's Meteorological Service of Canada
to warn population of two types of snow events reducing visibilities in blowing snow:
Environment Canada
Environment Canada , legally incorporated as the Department of the Environment under the Department of the Environment Act Environment Canada (EC) (French: Environnement Canada), legally incorporated as the Department of the Environment under the Department of the Environment Act Environment...
's Meteorological Service of Canada
Meteorological Service of Canada
The Meteorological Service of Canada , also known as "The Canadian Weather Service", is a division of Environment Canada, which primarily provides public meteorological information and weather forecasts and warnings of severe weather and other environmental hazards...
to warn population of two types of snow events reducing visibilities in blowing snow:
- Lake effect snowsqualls which are generated by cold arctic air moving over unfrozen water of lakeLakeA lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
or seaSeaA sea generally refers to a large body of salt water, but the term is used in other contexts as well. Most commonly, it means a large expanse of saline water connected with an ocean, and is commonly used as a synonym for ocean...
. These will reduce visibilities to less than 1 km and produce large accumulations of snow on the ground along narrow corridors in leeWindward and leewardWindward is the direction upwind from the point of reference. Leeward is the direction downwind from the point of reference. The side of a ship that is towards the leeward is its lee side. If the vessel is heeling under the pressure of the wind, this will be the "lower side"...
of the waters. Duration of these events can extend for days. - Frontal snowsqualls which are associated with a fast moving intense cold front in winter. Visibilities must be reduce to less than 1/2 km, wind over 40 km/h with a wind shift. Quantities of snow is not important with this type but intensity is heavy for a short period, typically 10 to 20 minutes.
See also
- Severe weather terminology (Canada)Severe weather terminology (Canada)This article describes Severe weather Terminology used by the Environment Canada's Meteorological Service of Canada. This article primarily describes various weather warnings, and their criteria. Related weather scales and general weather terms are also addressed in this article...
- SnowsquallSnowsquallA snowsquall is a sudden moderately heavy snow fall with blowing snow and strong, gusty surface winds. It is often referred to as a whiteout and is similar to a blizzard but is localized in time or in space and snow accumulations may or may not be significant.-Lake effect snow:When arctic air...
- Lake effect snowLake effect snowLake-effect snow is 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...
- Lake Effect Snow WarningLake Effect Snow WarningA Lake Effect Snow Warning is a bulletin issued by the National Weather Service in the United States to warn of heavy snowfall amounts that are imminent from convective snow generated by very cold airmass passing over unfrozen lakes...