An average figure is 10 inches (25 centimeters) of snow is equal to 1 inch (2.5 centimeters) of water. Heavy, wet snow has a high water content; 4 to 5 inches (10 to 12 centimeters) may contain 1 inch (2.5 centimeters) of water. A dry, powdery snow might require 15 inches (38 centimeters) of snow to equal 1 inch (2.5 centimeters) of water.