One month ago, Idaho’s snowpack was in a dismal state.
Every major basin had below-average snow accumulation. Some had less than 10 percent of normal for mid-November.
A few good snowstorms made a huge difference. By Thursday, measurements taken by the U.S. Natural Resources Conservation Service show full to above-average snowpack in about half of the state’s drainages, including most of southern Idaho, where the majority of our food supply grows.
Some of the most important basins for irrigation and water supply, including the Snake River area above the Palisades Reservoir in eastern Idaho, the Owyhee mountains and the basins north and east of Boise, had well above 100-percent snow accumulation.
There’s no doubt storms hitting Idaho over the past week have been the big factor in this snowpack turnaround, said Troy Lindquist, a hydrologist for the National Weather Service in Boise.
And more good news is on the way.
“It looks like we’re going to stay in a pretty active weather pattern for a while, say for the next seven days,” Lindquist said Thursday.
That’s especially true in southern Idaho, he said.
Looking further out, Lindquist said the La Nina pattern in place this winter should lead to cooler temperatures and heavier precipitation in Idaho.
“That doesn’t mean it’s going to be, like, double normal,” he said. “Right now we can’t forecast those kinds of details.”
The reality is that Idaho’s water supply outlook wasn’t as bad as it seemed a month ago, said Ron Abramovich, a water supply specialist for the Natural Resources Conservation Service.
Yes, the snowpack was way behind schedule. But heavy rainfall in October soaked the soil and spiked stream flow all over Idaho, Abramovich said. Now, freezing temperatures should lock that moisture in place through winter.
So when the snow melts in the spring, the soil won’t soak up as much water because it’s already close to saturated, Abramovich said.
“The fall rains set the stage for us,” he said. “It’s like a bank account.”
Taken together, recent snowfall, weather expectations and fall rains set up Idaho for a strong supply of water when irrigation season begins in April.
Both Abramovich and Lindquist cautioned, though, that nothing is guaranteed.
“It’s early,” Lindquist said. “We’ve seen this before where things are really going in December and then it shuts off in January.”