Monday, April 8, 1996 | 11:59 a.m.
Although Mount Charleston's solid white peak may look like a lot of snow, the 8.1 feet of melting snow in one canyon won't translate into much runoff to the Virgin River.
Dave Doughty and Gerald Miller of the U.S. Department of Agriculture's annual spring snowpack survey discovered this year's snow has only 47 percent of last year's snow-water content.
That means the Virgin River will get about 30,000 acre-feet -- or 71 percent of normal -- as the snows melt between April and July.
The Virgin River, running through southern Utah and Nevada, is fed by snowpack from surrounding mountain ranges.
Doughty and Miller trek the Spring Mountains in snowshoes each spring to measure the snow and its water content at four sites.
While most of the snows on Mount Charleston will melt and sink into the groundwater, the snowpack measurements help predict how close to normal water supplies will be.
In 1993, for example, Rainbow Canyon had 8.1 feet. In 1969, that depth was 9.8 feet and in 1952 it was 8.2 feet, according to records kept by the Agriculture Department.
Forecasters have been climbing Mount Charleston since 1941 to collect the snowy scenario for spring runoffs, Doughty said. It helps predict flows in the lower Colorado River basin.
The average snow depth at four snow survey sites in the Spring Mountains was 21 inches, or equal to 7.4 inches of water.
The Agriculture Department's Natural Resources Conservation Service, the National Weather Service and the U.S. Geological Survey have collected snowpack levels from Western mountains for more than 50 years at 1,600 different sites.
While the Colorado River, which feeds Lake Mead, is also expected to average below normal, water supplies in Southern Nevada should be all right in the Las Vegas Valley, according to Patricia Mulroy, general manager for the Southern Nevada Water Authority and the Las Vegas Valley Water District.
The river is operated on a system of dams that form lakes such as Mead, and dam operators can adjust the flows to meet the downstream demand. And upriver, the news sounds better.
For Arizona's Lake Powell, the estimate runs to 115 percent of normal with 8.9 million acre-feet flowing between April and July.
The collection sites for measuring Southern Nevada's mountain snows are located in Kyle, Rainbow and Lee Canyons.
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