Weather Links/Resources

The climate data report I ordered lists precipitation. What types of precipitation does that include? What is Liquid Equivalent Precipitation?

Sometimes people mistakenly try to determine the amount of water in a fresh snowfall by using a rule of thumb 10 to 1 ratio, assuming ten inches of snow melts to one inch of water. The problem with using this single ratio is that the density of snow can vary greatly from storm to storm and location to location. An extremely heavy, dense snow can have a ratio of only 3 to 1 (3 inches of snow melt to one inch of water), while very light snow can have up to a 100 to 1 ratio. That means only 1 inch liquid water can result in 100 inches of snow!

What is the difference between snowfall and snow depth?

Snowfall is the amount of fresh snow that has fallen during the 24-hour measurement period, while the snow depth is the total amount of snow on the ground and includes both old and new snow. Snowfall is measured to the nearest 1/10th of an inch while snow depth is measured to the nearest inch.

The climate data report I ordered lists precipitation. What types of precipitation does that include? What is Liquid Equivalent Precipitation?

The amount of precipitation listed on a climate report is the Liquid Equivalent Precipitation. This value includes the melted amount of any frozen precipitation (e.g., snow, sleet) that may have fallen in addition to any rain. Why is this frozen precipitation collected and then melted before being measured? The density of liquid water is constant; however, the density of frozen precipitation can vary greatly. One inch of "heavy" snow contains more water than one inch of "light" snow. Measuring the liquid equivalent of frozen precipitation can indicate the actual amount of water that fell, regardless of the type of precipitation. These values can also later be used in calculating ground water issues when snowmelt occurs.