When it rains, it's pretty easy to see how much water stacked up from a particular storm, but when it snows it's a little more difficult. Most of the time, the fallen snow has to be melted down and then measured as if it were rain. Since snow contains less water per flake than a rain drop, it naturally takes a larger volume of snow to amass the same water content of a smaller measurement of rain. Well, there's a pattern that shows up where in advance we can get an idea of how much snow is going to fall from a storm if we know how much water it can put down. Here's a conversion chart showing that pattern. The 'standard' conversion at about 32 degrees, is a 10:1 ratio...Meaning, if you melted down 10" of snow, you would have 1" of water.