Current State of the Cryosphere in Canada

Current State of the Cryosphere in Canada - Snow

Most Recent Snow Water Equivalent Map for Canadian Prairies

Documentation for Snow Water Equivalent (SWE) Map:

The colour filled contours depict variations in snow water equivalent (SWE) that have been derived from passive microwave satellite data. Generally, two consecutive orbits are required to cover the Prairie provinces. There may be some small areas with no data coverage on any given day. Since snow cover is essentially water in a frozen state, SWE represents the depth of water (mm) that would be produced if the snow was to melt. Information on SWE conditions is extremely important in forest fire modelling, flood forecasting, hydroelectric power production and watershed management. The wet snow symbol indicates that the snow cover at that location is either melting or very shallow (<10 cm) and derivation of SWE is not possible. Point measurements on the map indicate snow depth. The upper number is the depth of snow (cm) measured at Meteorological Service of Canada meteorological stations on the date indicated in the legend. The lower number, if present, is the normal snow depth for that date averaged over the 1971-2000 period.

Note: Starting with the December 1, 1999 map, a new SWE algorithm that takes into account forest cover effects on the satellite data is being used with the previously developed prairie SWE algorithm to provide more representative SWE values over the boreal forest region on the maps (i.e. north of the treeline). The maps generated in the previous winter seasons used the prairie SWE algorithm over the entire map area and the derived SWE values over the boreal forest region tended to be an underestimate of reality.

For further information on this product please visit the Passive Microwave Algorithm Development section, or contact Anne Walker at Anne.Walker@ec.gc.ca

Other Products Deviation From Normal SWE:

A new set of map products has recently been developed that provides information on how the current snow cover conditions compare to "normal". Using the historical record of SSM/I satellite data (1988 to 2011), maps of "normal" SWE have been produced for January 1, February 1, and March 1. The SWE map generated for these dates are compared with the "normal" to produce two "deviation from normal" map products.

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