PHILADELPHIA, PA — What is up with the weather? Yes, we have seen some freaky storms over the past few years. Global warming is expected to cause volatile weather patterns. Indeed, that is what we have been experiencing; however, overall the Northern Hemisphere is showing a steady decline in snowfall.
NOAA:
Average of monthly snow cover extent anomalies over Northern Hemisphere lands (including Greenland) since Nov 1966. Right: Seasonal snow cover extent over Northern Hemisphere lands since winter 1966-67. Calculated from NOAA snow maps. From BAMS State of the Climate in 2009 report.
Northern Hemisphere average annual snow cover has declined in recent decades. This pattern is consistent with warmer global temperatures. Some of the largest declines have been observed in the spring and summer months.