La Niña has delivered as advertised in Idaho this winter, leaving robust snowpack levels across the state and giving farmers hope that rivers and reservoirs will have ample water supplies to nourish crops during the summer.
State and federal hydrologists say the snowstorms that battered the state between mid-December and February built snowpack levels that are at or above 30-year averages in mountain ranges from Coeur d'Alene to Ketchum. An estimated two feet of water in the form of snow sits above the Boise River - water for crops along the way, as well as for this summer's floaters and fishermen.
The highest levels are recorded in northern Idaho, where some lower elevation snowpacks are close to 200 percent of average, according to reports released last week by the Idaho Water Supply Committee.
Last fall, meteorologists predicted that La Niña conditions developing in the Pacific Ocean would deliver a steady and prolonged dose of snow, rain and cooler temperatures to the Northwest this winter.
"And that's exactly what we saw," said Jay Breidenbach, senior hydrologist for the National Weather Service. "The water supply numbers are looking quite good. We should see some improvement there in long-term drought."
Still, state water officials say unpredictable spring weather remains a wild card.
Last week, Idaho Water Resources Director David Tuthill told lawmakers that Idaho's healthy snowpack lessens the likelihood the agency would issue curtailment orders this summer for southern groundwater pumpers. But Tuthill and others warn that a warm, dry spring could quickly alter such rosy forecasts.
"Things look good now. But we're not out of the woods yet," said Tuthill, who last summer threatened to shut down groundwater pumps used by hundreds of farmers and businesses in the Magic Valley.
Across the state, snowpack levels are generally 95 percent to 130 percent of average, well above levels recorded last year but lower than snowpack data collected at the same time in 2006, according to mid-March reports.
Northern Idaho, battered by heavy snowstorms in January and February, has yet to experience significant melt-off, with the Panhandle and Clearwater River Basin each reporting snowpack levels well above average. At higher elevations, mountains in the Panhandle and Clearwater areas reported snowpack exceeding 8 feet on March 1, according to the data.
Meanwhile, the Boise River Basin had dropped a bit to 97 percent of normal, according to hydrologists.
In the mountains above Boise, about two feet of water rests in still-frozen snows, Breidenbach said. The amount of water in that snow is about 97 percent of normal, which should replenish the basin's three reservoirs - Lucky Peak, Anderson Ranch and Arrowrock - once all the snow melts this spring, he said.
"If you were going into the mountains near Mores Creek, there is 29 inches of water on the ground there," he said. "That's more than two feet of water sitting on the ground up there, and that's normal.
"That's the water the farmers and everyone here in the Valley depends on to get us through these summer months."
Overall precipitation has been about 107 percent of normal since Oct. 1 in the Boise Basin, he said.
State and federal officials say the weather so far this month - a trend of warm days, cool nights and little moisture - has allowed rivers and streams to manage low-level snow melt. Those conditions have diminished the chances of severe flooding across the state, though hydrologists say the Weiser River has the highest potential of Idaho's major rivers for spring flooding.
The snowpack levels across Idaho are also good news for the state's network of reservoirs, many of which were depleted last year to provide water during a hot, dry summer. In Idaho, the last eight years have been characterized by drought, with the pattern last interrupted by above-average precipitation in the 2005-06 winter.
The latest data is also a boon to anglers, who rely on steady streamflows in Idaho's 19 river basins to maintain healthy fish populations, and rafters and kayakers who seek whitewater conditions created by plentiful flows.
"Most of the rivers throughout the state are forecast to flow (at) near-normal volumes throughout the summer," the report said.
Idaho Statesman reporter Kathleen Kreller contributed to this story.
