How do measure snow accumulation with drifts and high winds?
When snow is blowing and drifting, accurate and precise measurement of snow accumulation is a difficult task.
The trick in measuring snow consistently is simply finding a good place to measure and a firm surface for your ruler to set on. The measurement tools are simple: a ruler or yardstick that measures in inches and tenths of an inch.
It is recommended to use a snow board, which is a square piece of wood 16 inches on a side and painted white. Other surface options are wooden decks, picnic tables, and cars. Your measurement location should be 20 to 30 feet away from the house with an unobstructed view of the sky. Sidewalks are not recommended as good sites as they tend to accelerate melting of the snow. Also avoid grass, as snow tends to sit up on top of the blades of grass, while the ruler goes down to the ground.
With this set up, measuring new snow accumulation is straight forward, if there’s no wind. When the wind blows and the snow drifts, measuring snow is a challenge.
To deal with drifting snow, make measurements at a various places in your yard and then average them to get what is considered a representative measurement.
Snow is also measured with the standard rain gauge – an eight-inch diameter cylinder that collects precipitation. In winter the gauge can be equipped with a known amount of antifreeze so that the snow melts when it enters. This measurement yields the liquid water equivalent of the snow fall.
A good and free reference on snow is “The Snow Booklet: A Guide to the Science, Climatology and Measurement of Snow in the U.S”. It is available for download here.