Graph: North American Snow Cover on the Decline
As the world warms, the overall area of North America covered by snow is decreasing. One reason is because an increasing percentage of winter precipitation is falling as rain instead of snow in many locations. A Climate Central report found that between sea level and 5,000 feet in elevation across the Western U.S., a smaller percentage of winter precipitation is falling as snow.
However, the relationship is more complex at each local level. Rising temperatures can cause some individual storms to produce more snow, where temperatures are still well enough below freezing. That’s because for every 1°F rise in temperature, the atmosphere can hold 4 percent more water vapor. In turn, more water is available to fall as snow or rain.