Vidensdatabase

Official snow and ice measurements follow established National Weather Service (NWS) guidelines to ensure accuracy, consistency, and defensibility. These procedures are used across the meteorological community, including our team, to document snowfall totals for operational, legal, and billing purposes.

For full NWS standards, visit: https://www.weather.gov/gsp/snow

Key Steps in Official Snow & Ice Measurement

1. Use of a Snowboard (Measuring Surface)
   Measurements are taken on a flat, designated surface known as a snowboard, placed in an open area away from trees, structures, and drifting. This board is cleared periodically (no more than every 6 hours during a storm) to capture fresh accumulation accurately.

2. Measuring New Snowfall
   Snowfall is recorded as the greatest accumulation since the previous observation. Even if snow melts between bands or events, totals are added together to reflect the full impact of the storm. If snow melts on contact and never accumulates to 0.1 inch, it is recorded as a Trace (T).

3. Measuring Snow Depth on the Ground
   Once per day, the total depth of all snow and ice on the ground is measured using a calibrated measuring stick. Multiple readings may be averaged to account for drifting or uneven coverage. If less than 50 percent of the ground is covered, depth is recorded as a Trace (T).

4. Measuring Water Equivalent (Liquid Content)
   To determine the water content of snowfall, a core sample is taken and melted in a standardized precipitation gauge. This reveals the snow-to-liquid ratio, which helps distinguish wet, heavy snow from dry, powdery snow — an essential factor in impact reporting and snow-load assessments.

Why These Standards Matter

• Consistency: Ensures all totals are measured the same way

• Accuracy: Accounts for time, melting, drifting, and density

• Defensibility: Required for audits, insurance, and contractual documentation

Our Certified Snowfall Reports are built on these NWS standards and further enhanced through cross-verification using multiple data sources, including but not limited to NWS Storm Reports, CoCoRaHS, NOHRSC, radar imagery, and camera observations.