BOISE — Some record-setting weather in March has put Idaho’s snowpack — and ultimately its rivers, reservoirs and aquifers — in great shape heading into summer growing and recreation season, according to Idaho climate experts.
Members of the Idaho Water Supply Committee said Thursday that a barrage of snow and rain storms last month set a few 30-year precipitation records, saturating much of central and northern Idaho with precipitation measured at 200 to 300 percent above normal in some areas.
The snow and rainfall was less significant in the state’s southern half, creating conditions that reduced snowpack levels in some of the region’s mountains and basins.
Jay Breidenbach, senior hydrologist with the National Weather Service, says the March weather pattern that created the precipitation disparity was unique compared to recent years. Still, he said the state’s overall water supply outlook is robust.
“Even if we didn’t get any more precipitation we should have an adequate water supply across the state,” Breidenbach said.
That’s good news for Idaho tourism and agricultural industries, which rely on a steady water supply during the dry summer months.
As recently as 2008, state water managers considered shutting down water pumps that irrigate Magic Valley crops amid drought conditions.
But three consecutive years of ample winter snowfall and spring rains have all but evaporated any immediate concerns about drought.
“I think everybody is pretty excited that there should be no water shortages,” Breidenbach said.
Last month’s geographic storm contrast is among the starkest the committee has seen in recent years. Heavy late season snow and rain — along with warmer weather — are blamed for causing avalanches and mudslides in the Panhandle, while the lack of moisture has left rangelands along the southern border dry and dusty.
Water is in abundance in reservoirs across the state, with nearly all showing levels at or above average storage levels, according to the latest committee report. In response, reservoir managers are increasing flows to compensate for above-normal stream flows recorded in March and to make room for the expected snow melt in the mountains.
Snowpack levels in the Panhandle are at 120 to 130 percent of normal levels, heightening the risk of flooding heading into the warmer weeks ahead.
“There are concerns in some areas with a little too much water,” Breidenbach said.
But the deluge last month allowed some basins to make up for the drier months earlier this winter.
Before March, the Wood and Lost River basins in central Idaho were at below-average snowpack levels. Last month’s storms dumped nearly a whole winter’s worth of precipitation, restoring them to about average.
But the Big Lost and Little Lost basins could still use some help, according to Jeff Anderson, hydrologist with the National Resources Conservation Services in Boise.
“If things turn dry, they’re going to be the first to experience shortages,” Anderson said.
Meanwhile, basins like the Bear River in state’s southeast corner and the basins such as the Owyhee and Salmon Falls in the south and southwest had snowpack setbacks. But the reductions are no cause for alarm considering the health of the region’s reservoirs.
“Statewide, I would say the water supply is in great shape,” Breidenbach said.
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