How much snow falls per inch of rain?

January 28, 2009 11:16:17 AM PST
The snow ratio is a measure of the number of inches of snow in comparison to its liquid equivalent. That is, if the snow had fallen as rain, how many inches of rain would have fallen?

Erica's Answer:

The snowfall ratio can't be determined until the snow is accumulating. Weather observers at places like the Philadelphia Airport will collect the snow and melt it in order to give us a liquid equivalent.

The snowfall ratio in a typical winter storm is about 10:1. That means if 10 inches of snow fall, and you melted that snow, it would equal one inch of rain. That's one of the reasons it's so difficult to predict snowfall amounts. A range of 3"-6", for example, would only be 0.3" -0.6" of rain!

- Erica