With the exception of the Pacific Northwest, the western one-third of the United States is highly dependent on the winter snow pack for their yearly water supply. Although that area receives some moisture with the summer thunderstorm season, rainfall amounts tend to be too light and localized to offset the high summer evaporation rates. As with so many aspects of climate, the snow amounts the western mountain ranges receive each year varies greatly.
With millions of people dependent on winter snowfall, the years with limited snow can and does have strong economic repercussions. Fortunately, this past winter was a snowy one. The winter snow pack was rated as 100 to 500% above normal throughout much of the west. There is currently so much water melting that numerous reservoirs are overflowing with water leading to localized flooding concerns. 2011 will be a year with few water concerns, but everyone that lives in the west knows that each year is a roll of the dice and 2012 may not bring the same weather fortunes.