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Measuring Snowfall

Where and How to measure the snow

  1. Ideally, you want to measure snow on a snow board. You can make your own. It is just a clean, white board (about 2 X 3 feet). Place the board on the ground away from trees, buildings, fences, etc., as much in the open as possible. Allow the snow to accumulate on top of it and measure the depth with a ruler. Official NWS procedure states that the snowboard should be cleared every 6 hours - that strikes a balance between alleviating changes due to compaction versus melting.
  2. Less accurate alternatives include measuring on a deck or patio. These surfaces are more likely to be warmer and melt some snow or be sheltered by the house, etc., but it is a second choice.
  3. Measuring on the ground with no snow board works if there is no grass or the grass is extremely short and compact to the ground. If not, be sure not to jam the ruler down too far so that you are measuring the dirt and grass with your snow.
  4. Measuring on a driveway might work if the temperatures before the snow are well below freezing so that all the snow that falls accumulates and does not melt. If your driveway is paved, just use the ruler. If gravel, do not jam the ruler into the gravel, just penetrate the snow until you hit stone.

Other Important Tips on Measuring Snow

  1. Sampling - if you are not using a snow board, you might want to sample several locations and take an average. If windy conditions are causing drifting of snow, do not average in the drifts. Measure drifts separately.
  2. Drifts - Report drifts in feet (not inches). Only report if a drift is much greater than your snowfall. For instance, the wind blows all but a trace of snow off your snow board yet you have a 3 foot drift against your house.
  3. Reading the Ruler - measure the snow to the half inch, if possible. Always round upward. In other words, if you measure 5.75 inches, call in 6 inches.

National Weather Service
Weather Forecast Office Baltimore/Washington
43858 Weather Service Rd.
Sterling, VA 20166
Phone: (703) 996-2200
Page last modified: June 3, 2010 2:30 PM
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