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Found 10 records similar to Snowfall
The map shows the annual snowfall (in centimetres) based on the 30-year period 1941-1970. Snowfall is measured by inserting a ruler into the new snow at several points to obtain its depth and to estimate the degree of drifting or scouring that has occurred. The water equivalent of snowfall for most climatologically stations is estimated by simply assuming the freshly fallen snow has a density of 0.10 gram per cubic centimetre. On the average, this is a sound approximation over large parts of the country, but variations from 0.05 to 0.15 are common from storm to storm, and in the drier regions the average density is probably closer to 0.08 gram per cubic centimetre.
Contained within the 3rd Edition (1957) of the Atlas of Canada is a map that shows the snow cover data, referring primarily to the presence and total depth of a snow cover on the surface of the earth, across Canada. This is in contrast to data characteristics of snow cover depth, which increases by the occurrence of freshly fallen snow, but decreases by melting, wind action and settling. Two maps of these maps show the mean dates of the occurrence of first and last snow covers by one inch (2.54 cm) or greater. These are not necessarily the average dates to the beginning and ending of a continuous snow cover, since the snow cover may form and later disappear once or several times during a winter season.
This map shows the average maximum snow depth in centimetres computed over 18 winter seasons (1979 to 1997). Over southern Canada this usually occurs in January or February, while the time of maximum accumulation occurs much later in mountain areas and in the Arctic. The main features of the map are the pronounced maximum in snow accumulation over the western Cordillera, where snow depths can exceed several metres, with a secondary maximum over Quebec and Labrador. These maxima are related to their proximity to oceans, which act as sources of moisture and winter storms, and to the orographic effect of the mountains in the case of western Canada.
The map shows the mean maximum depth of snow in centimetres, the standard deviation of the mean maximum depth of snow, and the mean date of mean maximum depth of snow. The information shown on the map is compiled from 1961 – 1970 snow course data in conjunction with 1955 – 1972 snow depth data. An appreciation of the quantity of snow in storage within a drainage basin during late winter is critical to spring flood forecasting. As well, decisions regarding overland transport and wildlife control can be rationally taken.
Over southern Canada maximum snow depth usually occurs in January or February, while the time of maximum accumulation occurs much later in mountain areas and in the Arctic. The main features of the map are the pronounced maximum in snow accumulation over the western Cordillera (British Columbia and Yukon), where snow depths can exceed several metres, with a secondary maximum over Quebec and Labrador. These maxima are related to their proximity to oceans, which acts as sources of moisture and winter storms, and to the orographic effect of the mountains in the case of western Canada. The two maxima are linked by a band of higher snow accumulation that follows the boreal forest zone; this is a preferred track for winter storms.
Contained within the 5th Edition (1978 to 1995) of the National Atlas of Canada has a large that shows the extent of permafrost and abundance of ground ice; mapping units are based on physiographic regions. Point data on map give permafrost temperature and thickness for specific sites. The second, smaller, map shows the mean annual ground temperatures. Graphs show four shallow temperature profiles (to 25 metres depth), and four deep temperature profiles (to several hundred metres depth).
Contained within the 5th Edition (1978 to 1995) of the National Atlas of Canada is a map that shows relief using twelve height classes for land areas, eight depth classes for water areas. No populated places shown on map.
This map shows the median date of snow-cover onset (defined as the first date with 14 consecutive days of snow cover greater than 2 centimetres in depth) computed over 18 winter seasons (1979 to 1997). In areas with permanent or semipermanent snow cover (for example, Arctic ice caps) or in areas with irregular or ephemeral snow cover (coastal British Columbia), researchers were unable to compute the median values. The main feature of the map is the rapid southward extension of snow cover over Canada during the September to December period. The moderating influence of Hudson Bay can be seen over northern Quebec, where snow cover starts later than in the equivalent latitudes west of Hudson Bay.
Contained within the 5th Edition (1978 to 1995) of the National Atlas of Canada is a plate with seven maps. The first maps shows mean annual precipitation for Canada. Four additional maps shows mean annual precipitation for four separate months. The final two maps show mean growing season precipitation and mean number of days with measurable precipitation.
Contained within the 3rd Edition (1957) of the Atlas of Canada is a plate that shows two maps for the annual total precipitation. Annual precipitation is defined as the sum of rainfall and the assumed water equivalent of snowfall for a given year. A specific gravity of 0.1 for freshly fallen snow is used, which means that ten inches (25.4 cm) of freshly fallen snow is assumed to be equal to one inch (2.54 cm) of rain. The mean annual total precipitation and snowfall maps on this plate are primarily based on thirty-year data during the period 1921 to 1950 inclusive.