G.18. USDA/NRCS Snowfall Telemetry (SNOTEL) network
- Purpose of network: collect snowpack and related climate data to assist in forecasting water supply in the western U.S.
- Primary management agency: NRCS.
- Data website: http://www.wcc.nrcs.usda.gov/snow/.
- Measured weather/climate elements:
o Air temperature.
o Precipitation.
o Snow water content.
o Snow depth.
o Relative humidity (enhanced sites only).
o Wind speed (enhanced sites only).
o Wind direction (enhanced sites only).
o Solar radiation (enhanced sites only).
o Soil moisture and temperature (enhanced sites only).
- Sampling frequency: 1-minute temperature; 1-hour precipitation, snow water content, and snow depth. Less than one minute for relative humidity, wind speed and direction, solar radiation, and soil moisture and temperature (all at enhanced site configurations only).
- Reporting frequency: reporting intervals are user-selectable. Commonly used intervals are every one, two, three, or six hours.
- Estimated station cost: $20000 with maintenance costs approximately $2000/year.
- Network strengths:
o Sites are located in high-altitude areas that typically do not have other weather or climate stations.
o Data are of high quality and are largely complete.
o Very reliable automated system.
- Network weaknesses:
o Historically limited number of elements.
o Remote so data gaps can be long.
o Metadata sparse and not high quality; site histories are lacking.
o Measurement and reporting frequencies vary.
o Many hundreds of mountain ranges still not sampled.
o Earliest stations were installed in the late 1970s; temperatures have only been recorded since the 1980s.
USDA/NRCS maintains a set of automated snow-monitoring stations known as the SNOTEL (snowfall telemetry) network. These stations are designed specifically for cold and snowy locations. Precipitation and snow water content measurements are intended for hydrologic applications and water-supply forecasting, so these measurements are measured generally to within 2.5 mm (0.1 in.). Snow depth is tracked to the nearest 25 mm, or one inch. These stations function year around.
