Water Availability in Western States Measured : Snow Survey Provides Cold Facts

Standing in front of a blue diamond marker on a lodgepole pine, Richard Fike raised a long aluminum tube and drove it straight into the snow, pushing and turning until he felt the end bite into the ground.

“As long as you keep that thing moving, you’re all right,” he said. “If you let it stop, it’s hernia city.”

Fike, a hydrologist for the U.S. Soil Conservation Service, was passing on a few snow surveying tips to some of the staff at Crater Lake National Park.

Measurements of snow depth and weight taken near Annie Springs and at park headquarters here at Crater Lake help the agency predict how much water will be flowing in the Rogue River and other Cascade Range drainages this summer.

The park’s two snow survey courses, where measurements are taken throughout the snow season, are among 1,500 in the West the service takes into account to predict the runoff from the snowmelt.

Snowmelt Feeds Streams

“Mother Nature’s reservoir is the mountain snowpack,” said Stan Fox, the snow survey supervisor in the Soil Conservation Service office in Portland. “In the Western United States, about 75% of stream flow comes directly from snowmelt.”

Farmers keep up with snowmelt readings. They decide how much to plant, and which crops, depending partly on how much water they can expect in the dry season. Water system officials use the snowmelt figures to help set reservoir levels.

“Whitewater rafters call us all the time for forecasts,” Fox added. “Backpackers want to know the snow level and how long the snow will last so they can go camping.”

The snow survey dates from the late 1920s, Fox said, noting that in the mid-’30s the Dust Bowl placed greater attention on the West’s limited water supply. “The country . . . became very interested in water and trying to predict how much water would be available,” Fox said.

The technique of correlating the depth and weight of snow in the mountains to the amount of water that will run off when the snow melts dates back to 1906, when James Church, a humanities professor at the University of Nevada-Reno, got interested in the idea.

First Sampling Set

“He laid out snow courses on Mt. Rose,” Fox said. “And he developed the first snow sampling set. It was a hollow tube made out of steel, one piece 10 feet long. He would go marching up that mountain and take all kinds of samples.”

After a number of years of comparing snow depths on Mt. Rose in the winter and the level of Lake Tahoe in the summer, Church was able to predict the lake level from the snow measurements.

“From there it kind of snowballed and we got into the snow survey program,” Fox said.

The Soil Conservation Service handles stream flow predictions in Alaska, Washington, Oregon, Nevada, Idaho, Utah, Arizona, Colorado, Wyoming and Montana. California handles its own surveys.

In Oregon, 147 snow courses are sampled by hand and 70 are automated SNOTEL--short for Snow Telemetry--sites.

Monthly Samples

The snow courses are sampled each month from the first of the year until the end of the snow season, which runs until June at Crater Lake.

Here, the courses are sampled by park personnel, but the U.S. Forest Service, irrigation districts, ski clubs and snowmobile clubs handle others.

The Annie Springs course was established Jan. 25, 1929.

Red and yellow striped poles mark the ends of the 1,000-foot straight line that lies just out of range of the snowblowers that clear the road through the park.

A two-person team samples the course, driving an aluminum tube into the snow. The tube is made of eight 30-inch sections that can be added on to handle snow up to 20 feet deep.

Measurement Technique

Fike packs the tube in snow to get it cold before taking a sample. That way the core won’t stick inside.

The depth of the snow on the outside of the tube, as well as the inside are recorded. Then the tube is weighed. Each ounce translates into an inch of water.

While the snow courses are sampled once a month, the SNOTEL sites transmit daily information automatically.

First installed in 1980, they use big stainless steel pillows filled with antifreeze to sense the weight of the snowpack.

Weight readings, along with temperature and precipitation measurements, are coded into radio signals, then sent to a computer in Portland.

“They don’t use satellites,” Fox said. Instead, the signals are bounced off ionized particles in the trails of meteorites.

Meteorite Relay

“They just start broadcasting and pretty soon one (meteorite trail) will show up in the right place, bounce a signal down, and it will come into the master station. There are billions of meteorites a day,” he said.

Fike said courses on Mt. Hood and at Crater Lake regularly give the deepest snow measurements in the West.

Measurements in the spring of 1974 showed 128 inches of water in the snow at Mt. Hood and 104 inches at Crater Lake.

“The snowpack probably would be a little more than twice that,” Fox said.

The snowpack produced stream flows about 50% above normal that summer, but just three years later, the Rogue River was down to 43% below normal, Fox said.

This year the Rogue is expected to run about 20% below normal.