Snowpack makes water supply look solid

There's a silver lining to those snow-filled clouds engulfing the Cascade Mountains.

The string of snowstorms in recent weeks has wreaked havoc with drivers, made it the state's mostly deadly avalanche year in more than two decades, and raised concerns of lowland flooding.

But it has brought cautious smiles to farmers, suppliers of drinking water and power companies running hydroelectric dams.

"We were really nervous in December, before Christmas, because the snowpack wasn't looking good. But with all the snow we've gotten, we're pretty excited," said Tom Monroe, operations manager for the Roza Irrigation District.

The district supplies water to farmers in the heart of the Yakima Valley, and, thanks to the intricacies of the state's water laws, is one of the first to get water cut off during droughts.

The federal Natural Resources Conservation Service on Monday put numbers to what everyone knows: There's a lot of snow in the Cascades.

Statewide, the amount of water stored in mountain snow was 40 percent above average for this time of year according to the service, which runs a string of automated snow gauges based high in the mountains. In the central Cascades it's even higher, at 46 percent above normal.

We should have enough water for the coming year even if we don't get any more snow the rest of the season, said Scott Pattee, a water-supply specialist with the service. That amount of water rivals the last major snow year here, the winter of 1998 and 1999, when Mount Baker set a world record for total snow accumulation at 1,140 inches.

Don't start counting on a run at that record, however. The Mt. Baker Ski Area has logged 528 inches so far this year, compared with 745 inches at the same time in 1999.

But drinking-water managers like Seattle Public Utilities' Dave Hilmoe aren't worried about record-book trivia. Hilmoe's eye is on the snows feeding the Tolt and Cedar rivers, the sources of Seattle's drinking water.

"It's looking very good. We've got more snow right now than we usually do by early April, as long as we keep it," he said.

One problem scenario is a surge of warm, rainy weather — the infamous Pineapple Express — that can quickly melt snow at low elevations. That would release too much water at once to store in reservoirs.

That possibility is also a concern for disaster-response officials preparing for the possibility of winter floods if all that snow was to melt quickly.

"That's one of the things we fear the most this time of year," said Jeff Bowers, acting director of King County's Office of Emergency Management.

The risk is heightened this year, because the colder weather has translated into more snow at lower elevations, said Pattee. That's where a sudden bout of warm weather can have the biggest impact.

That risk has carried over to avalanches, which have killed nine people in Washington already this year, including hikers, snowshoers, snowmobilers and snowboarders. That's more than any year since 1985, the first year for which statistics are available from the Northwest Weather and Avalanche Center's Web site. The previous record of seven deaths was the winter ending in 2004.

Meanwhile, Seattle City Light, which relies on dams for most of its power, isn't quite so enthused about the snow.

That's because the biggest dam it runs is in the northeast corner of the state, on the Pend Oreille River. The water there comes from the Rocky Mountains, where snowpacks are much closer to average.

Warren Cornwall: 206-464-2311 or wcornwall@seattletimes.com