Dr. Gerdel: Sierra Snow Man
For a complete, illustrated history of the Central Sierra Snow Lab, click here.
The Sierra Nevada snowpack is without a doubt the Far West's most valuable natural resource — not for the economic benefit of winter
sports, but because it supplies water runoff to California and western Nevada. The snowpack is a vital asset that provides high-quality melt-water to millions of people, as well as to industry, recreation,
fisheries, agriculture and hydroelectric power generation.
In the early 1900s, Dr. James Church, a University of Nevada arts and classics professor, began a systematic study of the snowpack in the Truckee
-Tahoe region. Church pioneered the use of a hollow tube to determine water content in the snowpack. This simple, yet crucial tool allows hydrologists to predict water runoff and provides important data for
successfully managing reservoir systems.
Dr. Church made many important contributions to our understanding of the Sierra snowpack, but he was not
a trained scientist and could not delve into the highly complex physics inherent in this massive frozen reservoir. The first stages of this critical research began during World War II when government physicist,
Dr. Robert Gerdel, moved to Sacramento to establish the Central Sierra Snow Laboratory (CSSL) at Soda Springs, California, near Donner Pass.
In the early 1940s, Dr. Gerdel was the lead physicist at the U.S. Weather Bureau and
Technical Director of the government's newly-formed Cooperative Snow Investigations Research Program (CSIRP). One of his first assignments was to design and supervise
the construction of three national snow laboratories in the mountainous West. After considerable research, Dr. Gerdel located the labs in central Oregon, at Donner Pass,
and near Glacier Park, Montana. The sites reflect three distinct winter-precipitation regimes; mostly rain with some snow, mostly snow with some rain, and exclusively snow, respectively.
Robert Gerdel was born in St. Louis, Missouri, on October 4, 1901, but grew up at
Escanaba, Michigan. When he was 12 years old, a botched surgical procedure left him clinically deaf. A doctor had performed a successful tonsillectomy on the boy's kitchen
table, but an infection soon set in that permanently damaged his ear canals. Losing your sense of hearing is a life-changing event, but Gerdel never let this physical
handicap interfere with his plans to become a scientist. Although his high school principal tried to have him committed to the Michigan School for the Deaf, Gerdel
successfully persuaded the administrator to give him a chance. He learned to lip-read, checked the lecture notes of his fellow students, and graduated with good grades.
After high school, Gerdel attended Michigan State College of Agriculture and Applied
Science (now Michigan State University) and graduated with a BS in Soil Physics and Chemistry. Not only was the coursework challenging, two of his college professors
dropped him from their classes due to his lack of hearing. Gerdel went on to earn masters and doctorate degrees from Ohio State University.
In 1943, Dr. Gerdel and his wife and son moved to Sacramento where he spent two years designing the infrastructure of
the snow laboratories. While the physical facilities of the Central Sierra Snow Lab were still in the planning stages, Gerdel installed temporary weather instruments behind the Soda Springs Hotel near
Donner Pass. For a period of time, he and Dr. Church shared a small empty cabin behind the Soda Springs gas station, which they used as a base to conduct their related yet separate
research. In 1943, Dr. Gerdel supervised the initial construction of the CSSL buildings and installation of the new equipment. In
the first year of the lab's operation, Dr. Gerdel and his staff produced the nation's first comprehensive reports on instrumented studies of thermodynamics and hydrodynamics of deep, high mountain snow packs.
At the Central Sierra Snow Lab, Dr. Gerdel pioneered the use of radioactive material to
measure the water content and density of the snowpack. During the summer months, individual isotopes of radioactive zinc were placed in remote locations north of Donner
Summit and a Geiger counter was suspended over each one. The Geiger counters measured the pulses or oscillations caused by gamma rays emitted by the
radioisotope — the oscillations varied depending on the snowpack's density and water content. The radio-transmitted measurements gave the CSSL scientists constant, real
-time data, a real breakthrough in the science of snow surveying.
Today, these "isotopic profiling snow gauges" first designed by Dr. Gerdel are more sophisticated and one of the most accurate methods for measuring snow
water equivalent. One version of a modern nuclear gauge utilizes two parallel, but separated vertical tubes, one of which contains the radioactive source, the other a detector. They are automatically raised out of their
underground holds and lifted slowly through the snowpack. A density reading is obtained every centimeter as the tubes slide through the snowpack, which yields the snow water equivalent.
The Donner Summit region of the Sierra proved to be a particularly well-suited area to
launch the CSIRP. Long-term weather records for locations in western United States snow-zones are relatively rare, but Southern Pacific Transportation Company
employees had begun measuring snowfall and snowpack at the railroad's Summit Station at Norden in 1878. Later, precipitation data from three different National
Weather Service sites in the area maintained the continuity of the region's weather measurements.
In addition to providing reliable conditions for studying the physics of a deep snowpack,
the Sierra snow lab was critically important to the federal and state control of California's water supplies and flood control. The research conducted there allowed
scientists and technicians to monitor snowfall and snow melt and to predict future needs of the State's water delivery system known as the Central Valleys Project (California aqueduct).
When Robert Wallace Gerdel died 20 years ago on March 27, 1987, at the age of 85, he left behind a legacy of accomplishments. Well-known as a
resourceful and professional physicist and engineer, Dr. Gerdel gained international recognition for his research work at snow hydrology laboratories in the U.S., Alaska and Greenland. Over
the span of his career, Dr. Gerdel wrote more than 50 scientific papers that were published in technical and professional journals.
Dr. Gerdel's early efforts to investigate and improve our scientific understanding of the complexities of the vital Sierra
snowpack laid the groundwork for a water management system that helped nourish and sustain the growth of California into an economic giant.