|Taking a snow core |
for a water equivalent measurement.
The adage "one inch of rain equals ten inches of snow" is a myth. It happens, of course, but only under certain circumstances. Observers should never "measure" snowfall by using the 10:1 ratio to convert the water in the gauge to snow depth. That's why we ask observers to measure the depth of new snow, and to measure the liquid water equivalent of that snow.
|A stellar dendrite snow crystal|
|30-year climatology of snow to water ratios. |
Credit: A Climatology of Snow-to-Liquid Ratio for the Contiguous United States Martin A. Baxter, Charles E. Graves, and James T. Moore, St. Louis University, October 2005. AMS Journal of Weather and Forecasting
|Snow falling on Saturday|
Another 0.8 inch of snow on Sunday night melted to 0.06 inch water for a snow to water ratio of 13.3:1. So over a period of a little over 48 hours I measured 9.3 inches and snow to water ratios ranging from 6:1 to 13:1.
In general, the colder it is, the less dense the snow will be. Snow falling at 20°F will tend to be dry and "fluffy" while snow at 32°F will tend to be wetter and denser, the good-packing snowball-making, snowman-making kind of snow.