Several terms are used when talking about how much moisture is contained in a certain amount of snow. The most frequently used term is often liquid equivalent. This is the depth of water that would result from melting a sample of snow.
Liquid equivalent is the amount of measurable moisture if the snow were to have fallen as rain. This is where the infamous “10-to-1” ratio has its roots. The “10-to-1” ratio is the assumption that for every 10 inches of snow that falls, there is roughly 1 inch of actual moisture. This ratio is actually only an estimate and is based on snow forming in the 28-34 degrees F range.
If temperatures are colder, say in the 10-15 degree F range, estimates can be as high as 30-to-1 (30 inches of snow equal to 1 inch of moisture/precipitation). This is a simplified estimation because snow liquid equivalent is also subject to temperature and humidity above the surface as well. (Figure 1).
![Mark McNeely](https://www.no-tillfarmer.com/ext/resources/2018/Screen-Shot-2018-02-21-at-90140-AM.png%0A%20)
![Mark McNeely](https://www.no-tillfarmer.com/ext/resources/images/Screen-Shot-2018-02-21-at-90310-AM.png%0A)
![Mark McNeely](https://www.no-tillfarmer.com/ext/resources/images/Screen-Shot-2018-02-21-at-90355-AM.png%0A)
Often, with automated gauges, snow blows out of the gauge before it has a chance to melt. Therefore, estimates can be greatly under-measured. While we do have some heated rain gauges, they only activate once snow covers the sensor. If strong winds continually blow the snow around, it doesn’t have a chance to trigger the heater sensor and thus, is not measured.
Snow that is melted (either by the heater or by warmer temperatures the next day on non-heated rain gauges) and drips into the rain gauge is measured as liquid. The data from these gauges is the liquid equivalent of the accumulated snow.
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