OR-AMS November 13, 2006 Meeting Summary


Oregon AMS Chapter members gathered to hear Jon Lea present some information about the Natural Resource Conservation Service (NRCS) and its Snow Survey program. 


Mr. Lea began by presenting a history of the program, which began in the 1920s in both Washington and Oregon.  The program’s establishment followed the early 1900s discovery of a correlation between snowpack and streamflow.  Today, the Portland office of the NRCS serves as the “home” data collection site for much of the western U.S., where eight staff members gather to process and analyze the data.


Following a discussion about the program’s history, Mr. Lea proceeded to discuss the specific methods the NRCS uses to measure the snow.  There are three primary methods.  The first and oldest method is the “snow course”, where humans put on their snowshoes and collect snow depth and water weight using an aluminum “snow tube”.  In more remote places, observers in helicopters can measure snow depths using “aerial marker” posts.  And the third method, which is now the most common, is to use SNOTEL telemetry.  These are solar-powered systems that use “meteor burst beams” to communicate.  It’s a fascinating process where radio signals are transmitted between each SNOTEL site and the master collection station via a “bounce” off the meteor trails in the sky.  Today, there are over 800 SNOTEL sites, and most of the sites established since 1990 are funded by a sponsor (a city, government agency, or a power company, for example).


Next, Mr. Lea discussed the products that the NRCS and its Snow Survey program offer.  Forecast products include monthly water supply outlooks (January through June) and forecasts for seasonal volume, peak flows and stages, and recession.  Factors that influence the forecasts include snow-water equivalent (SWE), total precipitation, streamflow, reservoir levels, soil moisture, and spring temperatures.  Forecast challenges are many given that there are many unknowns early in the wet season and some of the physical processes that occur in watersheds are difficult to assess.  New model development will help improve forecast accuracy.


I’d like to thank Jon Lea for an informative and interesting presentation.



Drew Jackson

Secretary, Oregon Chapter of the AMS