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Found 10 records similar to Dates of formation and loss of snow cover
This map shows the median date of snow-cover loss (defined as the last 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 end date contours follow topography more closely than start date due to the influence of elevation on total snow accumulation and air temperature. The date of snow-cover loss has important implications for wildlife (for example, bird migration and nesting), vegetation, local climate and hydrology.
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.
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 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.
Nunavut lies in the Arctic, where cold temperatures mean that snow can fall at anytime in the year. Typically the ground is snow covered from September until June. Most of Nunavut has a dry Arctic climate receiving less than 200 centimetres of snow annually.
This measure is based on snow-tracking data from 25 established snow-transects in the Bow Valley. Most transect occur within corridors around the Banff townsite, but several reference transects are located in the Broader Bow Valley. Trends for this metric focus on wary carnivores (cougar, lynx, wolf, and wolverine) on transects within 5 km of the Townsite. Data collected include location, species presence, number of animals, days since snow, & snow-depth.
The measure is based on snow-tracking data from 3 established snow-transects in the Kicking Horse Valley. Trends for this metric focus on wary carnivores (cougar, lynx, wolf, and wolverine) though prey (ungulate) data will also be collected. Data collected include location, species presence, number, days since snow, & snow-depth.
Contained within the 5th Edition (1978 to 1995) of the National Atlas of Canada is a plate with seven maps. The first map shows mean annual snowfall in Canada. Four additional maps show median snow depth for four separate months. The final two maps show snow cover and maximum snow depth.
This paper presents an analysis of observed and simulated historical snow cover extent and snow mass, along with future snow cover projections from models participating in the 6th phase of the World Climate Research Programme Coupled Model Inter-comparison Project (CMIP6). Where appropriate, the CMIP6 output is compared to CMIP5 results in order to assess progress (or absence thereof) between successive model generations. An ensemble of six observation-based products is used to produce a new time series of historical Northern Hemisphere snow extent anomalies and trends; a subset of four of these products is used for snow mass. Trends in snow extent over 1981-2018 are negative in all months, and exceed -50 x 103 km2 during November, December, March, and May.
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.