Instuctor: Mark Williams
Telephone: 492-4794 or 492-8830


Web Sites
Problems and Challenges Measuring Snow
Methods of Measuring Snow Depth
Methods of Measuring Snow Water Equivalence
Oversampling of Snow on Niwot Ridge
Incredible Snow Falls

Web Sites for Snow Measurement Programs

Problems and Challenges in Measuring Snow

Methods of Measuring Snow Depth

  1. Snow stakes, permanent or seasonal deployment.
  2. Snow probes: essentially rulers that are stuck into the snow.
  3. Remote Sensing: not functional. Active microwave (Synthetic Apeture Radar) has potential but not yet functional for measuring snow depth.

Methods of Measuring Snow Water Equivalence (SWE)

  1. Gravimetric
    • Melt and weigh snow of a known volume. Cumbersome but effective.
    • Federal or Mt. Rose snow sampler. Long tube of known volume that is stuck into the undisturbed snowpack and retrieves a snow core that hopefully is continuous from the snow surface to the ground surface. The snow core is weighed and converted in SWE. Relatively fast and efficient. The California Cooperative Snow Survey has about 300 snow courses, all of which use this instrument to measure SWE.
    • Density cutter that goes into the sidewall of a snowpit and retrieves snow of a known volume, which is then weighed and converted into SWE.
  2. Snow Courses
    • Manual surveys require two-person teams to measure snow depth and water content at designated snow courses (fig. 6). A snow course is a permanent site that represents snowpack conditions at a given elevation in a given area. A particular snowpack may have several courses. Generally, the courses are about 1,000 feet long and are situated in small meadows protected from the wind.

    • Measurements generally are taken on or near the first of every month during the snowpack season. The frequency and timing of these measurements varies considerably with the locality, the nature of the snowpack, difficulty of access, and cost. On occasion, special surveys are scheduled to help evaluate unusual conditions.
    • NRCS conducts intensive training in snow sampling techniques, safety , and mountain survival. On-the-job training and an annual "west-wide" school develop the needed skills. The school has become known throughout the Western United States and Canada for its unique training program offered to NRCS employees and others engaged in the cooperative surveys. A critical part of the training is the overnight bivouac in a snow shelter the student constructs. Many graduates have credited this training with bringing them safely through unforeseen, hazardous situations.
    • The surveyor makes certain that the tube is clear of all snow and soil before taking the snow core sample. The team uses a strong, light-weight, graduated aluminum tube and a weighing scale.

    • One surveyor measures the snow depth while the other records data. From 5 to 10 measurements are taken at regular intervals along a snow course. Snow depth is measured by pushing the tube down through the snowpack to the ground surface and extracting a core.

    • In taking an accurate snow core sample, the surveyor must verify that the tube has reached ground level by examining the base of the tube and finding soil. After clearing out the soil from the tube, the surveyor determines the amount of water in the snowpack by weighting the tube with its snow core and subtracting the weight of the empty tube. An average of all samples taken is calculated and used to represent the snow course.

  3. Snow Pillows
  4. Radioisotope Gauges
  5. Precipitation gauges

Incredible Snow Falls

From the Snow Booklet, pages 41-44.

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