The purpose of this page is to provide an indication of how recent snow cover conditions over North America vary from the "average" or "normal" snow cover for the period. Plots have been updated every 6 to 7 weeks during the period of coverage. The anomaly map shown below is based on a 6 week period during the spring of 2004.

Snow Cover Anomaly

Red hues indicate below average snow cover; blue hues indicate above-average snow cover. [ View anomalies for previous periods].

[ View actual snow cover for previous periods ].

[ View mean snow cover for different periods of the year ].

These images are derived from the NOAA weekly snow cover product which is obtained from visible and passive microwave satellite data. The NOAA weekly data is binary in format (0 or 1) with grid cells (89 by 89 polar stereographic grid) coded with a '1' where it was determined there was more than 50% snow cover on the last day of the week. The digital data is available from the NOAA Climate Prediction Center.

• View snow cover anomalies for other 6-week periods since 1998 (North America)
• View snow cover anomalies for other 6-week periods since 1998 (Eurasia)
• Seasonal Snow Cover Extent Anomalies 1994/1995 to 1997/1998 (North America)
• Seasonal Snow Cover Extent Anomalies 1994/1995 to 1997/1998 (Northern Hemisphere)
• An explanation of the computation of the standardized anomalies, as displayed in the snow anomaly images