Dear Tom,
I like to look at annual precipitation totals for various locations. Does that number include melted snow at a 10:1 ratio?
Rick Nurse Harbor Springs, Mich.
Dear Rick,
The total annual precipitation listed for any locality includes all rain that has fallen and the melted water equivalent of all snowfall. It does not assume a 10:1 ratio for the water content of snow, but the actual amount of water melt. The water content of snow is highly variable, ranging from as low as 4:1 (four inches of snow for one inch of water)in heavy, wet snowstorms where the temperatures are holding around freezing to as high as 50-100:1 in an extremely dry and cold environment, as one might encounter at the South Pole. Frank Wachowski, who has been measuring Chicago’s snowfall since the 1950s, tells us the typical Chicago snow- rain ratio is about 10-12:1.