Measuring new snow falling on top of old snow
When new snow has fallen on old snow, it is necessary to measure the depth of the new snow along with the total snow depth.
Here are several ways to do this:
1. Use a Snow Board.
Snow boards are laid on top of the old snow, and are usually made of thin lumber or light material. The board should be light enough so they will not sink in the snow...but heavy enough not to blow away. They should also be painted white. After each observation, boards should be cleaned and placed in a new location. Snow boards or measuring areas like decks and patios should be wiped clean of snow every 6 hours if possible. Snow boards are also good for doing snow cores and measuring the liquid of the snow (see below).
2. If the old snow has settled and developed a crust, you may be able to insert the snow stick until you feel a greater resistance. Sometimes older snow has taken on a darker color. If so, you can cut a vertical core through the snow to get the new snow depth. See below.
3. Measuring the water content of the snow:
If you are using a 4” diameter rain gauge, then take the outer cylinder inside with the snowfall in it and let it melt. Pour the liquid contents into the calibrated inner cylinder. Sometimes the amount of melted liquid inside the outer cylinder may not be representative of the actual precipitation, especially if there was strong winds and considerable blowing snow. You may then want to take a core sample with the outer cylinder. Take the outer cylinder and push it straight down into the snow (or your snowboard) and cut out a biscuit of snow. Then use a flat surface or cookie sheet to slide under the cylinder so you can lift up the snow contents. Then let the contents melt and measure the liquid as done above.