Snowfall is measured in a very practical and low-tech way: with a ruler. To get a good average indication of snowfall in a selected area, the National Weather Service takes measurements from several locations, instead of just one, and then averages them out. In places where there is often heavy amounts of snow, tall poles are erected that can measure the white stuff when it accumulates up to several feet, or even meters, deep. Snowfall can also be measured using a heated rain gauge, which melts the snow into water, then converts it back to estimated snow levels by using the formula that one inch of rain water roughly equals 10 inches of snow. However, in North America, this method is not really used because it is not very accurate.