It’s no secret that the center of the country is suffering from an extended, exceptional drought and has been for quite a while. Last week’s huge snow storm, nicknamed by Kansas locals the “Blizzard of Oz” might have brought a lot of white flakes, but it didn’t do much to help relieve the desperate need for water. Why not? The reason is that lots of snow does not necessarily equal lots of rain.
Meteorologists measure snow in inches the same way we measure rain, but an inch of snow might translate into barely more than a trace of rain. How do we decide what the liquid water (rain) equivalent is? We use snow to liquid ratios.
In a “dry” snow, we often see huge flakes that stack up quickly, make fluffy snow mounds, and blow around easily. It’s the kind of snow that’s fun to watch, but not good for packing snow balls. The downside of this type is that the snow to liquid ratio is about twenty to one (although that twenty could range from ten to thirty or higher), which means that for twenty inches of snow, we would end up with just one inch of water after it melts.
In a “wet” snow, the liquid to water equivalent is more like four to one. Several inches of heavy, wet snow can make a difference in the water table once it melts. It’s also more likely to cause flooding if melts very quickly as is often seen in the spring in the Northern Plains.