Ground blizzard refers to a

weather Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmosphere, the ...

condition where loose snow or ice on the ground is lifted and blown by strong winds. This can occur in the absence of precipitation, and can even occur when the sky is clear. This is in contrast to "ordinary" blizzards, which are accompanied by heavy falling snow. They can be especially dangerous as they occur after a

winter storm A winter storm is an event in which wind coincides with varieties of precipitation that only occur at freezing temperatures, such as snow, mixed snow and rain, or freezing rain. In temperate continental climates, these storms are not necessa ...

has passed, when it is assumed that all forms of severe winter weather has ended.

Meteorological criteria

While the term "ground blizzard" is often associated with intense blowing and drifting snow conditions, there are specific criteria which must be met. Often such criteria will be determined by a country's governing weather agency or other similar body. In the U.S, according to the National Weather Service a blizzard is defined as having sustained winds or frequent gusts of 35 mph or more, visibility frequently below 1/4 mile in considerable snow and/or blowing snow, and the above conditions are expected to prevail for 3 hours or longer.

Environment Canada Environment and Climate Change Canada (ECCC; french: Environnement et Changement climatique Canada),Environment and Climate Change Canada is the applied title under the Federal Identity Program; the legal title is Department of the Environment ...

similarly maintains that widespread reduction of visibility to less than 400 meters due to snow and/or blowing snow and sustained wind speeds or gusts of 40 km/h or more must be present for at least 4 hours (6 hours for the Northwest Territories and Nunavut)

Types

There are 3 different forms of ground blizzards: # In horizontal advection conditions, the winds blow across the surface of the earth with very little if any large-scale upward motion. # In vertical advection conditions, the winds exhibit large-scale upward motion lifting the snow into the atmosphere creating drifting waves of snow up to 500 meters in height. # In thermal-mechanical mixing conditions, massive convective rolls form in the atmosphere and the blizzard may be observed from space with the blizzards convective rolls creating waves of snow (also known a
snow billows
resembling lake or ocean effect snow bands. The extreme conditions can quickly bury a two-story home and make breathing very difficult if not impossible if caught outdoors.

Climatology

Ground blizzards occur throughout the world, however unlike other winter storms,

topography Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary sc ...

either aids in their formation or prevention. The most important topographic element in a blizzard is the requirement for a vast amount of large open and relatively flat land. Any type of flora, especially coniferous forms, will catch any drifting snow significantly reducing the blizzard's effects. The environment must also support temperatures cold enough to prevent any snow on the ground from melting and bonding the ice crystals together. Ground blizzards are common in the American

great plains The Great Plains (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, a ...

in the wake of snowstorms producing light, dry snowfall that is more easily picked up by strong winds. They are also common in the

Canadian Prairies The Canadian Prairies (usually referred to as simply the Prairies in Canada) is a region in Western Canada. It includes the Canadian portion of the Great Plains and the Prairie Provinces, namely Alberta, Saskatchewan, and Manitoba. These provin ...

, Siberia, Northern China, and also Arctic and Antarctic regions during seasonal transition periods, such as the spring and fall.

Famous ground blizzards

* Blizzard of 1977 (Western New York and Southern Ontario)

References

{{reflist

External links

Animation of an extreme ground blizzard as seen from space

Definition of various weather terms including a ground blizzard

Snow or ice weather phenomena Blizzards fr:Blizzard (météorologie)#Blizzard de surface