Associations between snow cover extent and surface air temperature over North America

We find significant associations between regional snow-cover extent and surface air temperature across North America. In a large majority of cases when the extent of snow cover is above normal, temperature departures are negative. Conversely, negative snow departures are almost always associated with above normal temperatures. Regional correlations are highest in seasons when snow cover is most variable. The largest temperature departures are associated with anomalies of snow cover over the central portion of the continent. An examination of 500 mb heights across North America suggests that – though circulation anomalies doubtlessly contribute to the temperature departures observed in regions of anomalous snow – the presence of absence of snow strongly influences temperatures. This relationship is most apparent in situations of above average snow extent. Results of this investigation should be of interest to those studying middle and high-latitude climate dynamics and climate change from both an empirical and modeling perspective.