It's official - Idaho has one of the deepest June 1 snowpacks ever measured in the state, according to the Natural Resources Conservation Service. “In an average year up to about two-thirds of the snowpack melts during April and May,” said Ron Abramovich, water supply specialist with the service. That hasn't happened this year - and, in fact, snow has continued to fall at higher elevations. The risk: A sudden melt-off in June that could flood Idaho streams and rivers. Click below for the NRCS' full announcement.
NRCS ~ Natural Resources Conservation Service
HIGH COUNTRY STILL PACKING LOTS OF SNOW
June 3, 2011, Boise, Idaho. Snow Surveyors from the Natural Resources Conservation Service recorded one of the deepest June 1 snowpacks ever measured in Idaho. This year’s late season snows and slow snow melt provides more than enough water for users and creates a potentially threatening runoff season, especially in the upper Snake and Bear River basins.
“In an average year up to about two-thirds of the snowpack melts during April and May,” said Ron Abramovich, Water Supply Specialist with Idaho NRCS. “This year, the cool spring temperatures prevented high elevation snows from melting.”
“Not only do we have more snow, but there’s the potential for a quick runoff period. Warm temperatures in June will intensify the higher elevation snow melt,” Abramovich said. “More water in less time means the streamflow volumes will be much greater than normal.”
Generally, streamflows were above average in May and the peaks on most rivers are still to come. Over 80 of 120 Snow Telemetry sites that automatically measure snowpack conditions around Idaho showed the June 1 snow water content levels at or near record highs.
“Hot temperatures or rain during this critical time period when the snow is receding and soils are saturated, will send a flush of water down many streams and generate big flows,” Abramovich said.
Streamflow forecasts reflect the unusually high June 1 snowpacks. The forecasts around the state range from a low of 120% of average in central Idaho to over 300% in the Bear River basin.
“The potential for extreme flows can’t be overstated because of the enormous June 1 snowpacks and the continued wet weather pattern,” Abramovich said. “For up-to-date information on specific areas, visit our web site: http://www.id.nrcs.usda.gov/snow/.”
The full June Water Supply Report is posted on the web site. For current snowmelt and streamflow relationship analyses information, view the snow-stream graphs and streamflow graphs at: http://www.id.nrcs.usda.gov/snow/watersupply/peakflow.html.