Snow Ratio -- What Is It? | WeatherBug
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Snow Ratio -- What Is It?

March 1, 2021
By WeatherBug's Christopher Smith
Have you ever noticed that sometimes the snow is heavy and wet while other times it is fluffy and dry? The consistency of snow all comes down to a term called the snow ratio, or the ratio of water to snow.

You may be aware of the 10:1 snow ratio, meaning for 10 inches of snow, there would be about one inch of liquid water. However, often the snow ratio can be much higher or lower. For example, in the Mountain West snow ratios can be as high as 20:1, while in the South the ratio can be as low as 7:1.

So, what controls the snow ratio? There are a few factors.

First and foremost, the temperature is critical. If there are warmer temperatures at the surface and above, the snow will be heavier and wet, containing more water. The added water drives snow ratios down and that’s why it is common for lower snow ratios in the South and East where temperatures may be just cold enough to support snow.

An additional factor deals with the composition of the clouds above. If the clouds contain more ice crystals versus super cooled liquid water droplets, there will be less water contained in the snow and the snow ratio will be higher.

Finally, the wind can be an additional factor. If it is windy at and above the surface, snowflakes can break apart and actually limit accumulation on the ground, lowering the snow ratio.

Snow ratios are important in forecasting snowfall accumulations and can determine whether you’ll need a lot of strength or not to remove snow, depending on its consistency. In general, the colder it is, the higher the snow ratio and fluffier the snow will be for your area.

Source: weather.gov
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Story Image: Snow ratios depend on a variety of factors from the surface temperatures to the clouds above (pixabay.com).