Snow, Ice, Avalanches, and Glaciers - Mountain Geography: Physical and Human Dimensions - page 161

referred to as pipes, leading to a complicated internal “plumbing system” during the
snowmelt runoff period (Dunne and Leopold 1978; Barry and Gan 2011).
FORECASTING SNOWMELT-DERIVED WATER RESOURCES
In the western United States, the Cooperative Federal Snow Survey under the lead of
the Natural Resources Conservation Service is charged with taking measurements and
providing monthly reports on the status of the snowpack in different regions. This has
become a vital operation in water-supply forecasting (Davis 1965; U.S. Department of
Agriculture 1972; Palmer 1988; Pagano et al. 2004). Measurements are taken by two
different techniques. The traditional technique was developed in the early 1900s by Dr.
Frank Church, a professor of Romance languages at the University of Nevada at Reno,
for forecasting runoff down the Truckee River. His technique involved simply shoving a
length of pipe through the snowpack to the ground to capture a known volume of snow.
The snow volume, reduced to its liquid content, is called the snow water equivalent
( SWE ). This basic technique is still in use today at many snow survey courses located
throughout the country, where federal sampler tubes are used to take samples manu-
ally at several points along the snow course transect. However, this sampling method
is increasingly being replaced or supplemented by a unique automated system called
SNOTEL (SNO-pack TELemetry) that has been implemented at over 600 sites across
the western United States (Serreze et al. 1999). SNOTEL uses a large rubber or metal
bladder filled with antifreeze. As snow accumulates on the bladder, a pressure trans-
ducer calibrated in inches of water senses the load. These data are sent to receiving
stations using a solar-powered radio transmission system where signals are bounced off
the ionized trails of burning meteors (called meteor-burst transmission).
SNOW AND SNOWMELT RUNOFF AUGMENTATION
Considerable research and effort has gone into developing methods of increasing and
retaining the snowpack. They include installing fences in alpine grasslands, planting
more trees, and experimental methods of timber cutting that alternate cut and standing
patches of trees to preserve the snow from ablation (Martinelli 1967, 1975; Leaf 1975;
Jarrell and Schmidt 1990). Efforts toward artificial stimulation of precipitation ( cloud
seeding ) have largely been focused on increasing the snowfall in mountains (Weisbeck-
er 1974; Steinhoff and Ives 1976; Bruintjes 1999). Cloud-seeding studies have produced
contradictory results, and there are concerns about “sky water rights” and increased
mountain hazards. Often, people living downwind of seeding projects feel that they are
being deprived of some of “their water” others are concerned that increased precipita-
tion would lead to increased mountain hazards, such as snow avalanches and flooding.
It should be pointed out that not all snow in the pack becomes stream runoff. A number
of possible losses can and do occur as a result of soil infiltration, sublimation from the
snow surface, sublimation from snow in trees, and evaporation from the melting snow
surface (Avery et al. 1992; Niu and Yang 2004). Debate continues about the significance
of such losses, but in some areas of the western United States, basin efficiencies are on
the order of only 30-40 percent. It should be apparent that warm summers lead to high
evaporation rates. This in turn can severely limit the effectiveness of summer rainfall as