The latest precipitation levels and snowpack figures for Idaho are varying so wildly that hydrologists at the National Resources Conservation Service are calling it “March Madness.” Said Jeff Anderson, NRCS hydrologist in Boise, “Diverse conditions would be an understatement to describe the present snowpack situation in Idaho. Since March 1, we’ve measured one of the greatest one-month changes in snowpack on record.”
Measurements showed the snowpack decreased up to 22 percent in low- and mid-elevation southern Idhao basins including Bear, Blackfoot, Bruneau, Owyhee and Portneuf, dropping them to as much as 60 percent below normal; while March storms boosted the Panhandle snowpack up to 120 percent of normal. Many areas north of the Snake River Plain saw their snowpacks jump as much as 34 percent from the hit-and-miss March storms.
Click below for the full news release from the NRCS, which documents how storm after March storm moved through central and North Idaho but left parts of the south dry.
March snowpack levels vary widely across state
Boise, ID, April 9, 2012 – Hydrologists from the Natural Resources Conservation Service used the term “March Madness” to describe the results from the latest snow survey which shows a wide range of precipitation levels and snowpack amounts across Idaho. During March, storm after storm moved through central and northern Idaho but left parts of southern Idaho dry.
“Diverse conditions would be an understatement to describe the present snowpack situation in Idaho,” said Jeff Anderson, NRCS Hydrologist in Boise. “Since March 1, we’ve measured one of the greatest one-month changes in snowpack on record.”
According to snow survey and Snow Telemetry (SNOTEL) measurements, the snowpack either increased or decreased depending on the area. Warm weather melted some of the low and mid elevation snowpack in the southern Idaho basins of Bear, Blackfoot, Bruneau, Owyhee, and Portneuf decreasing the snowpack up to 22 percent. With little March snowfall across southern Idaho many of those basins have snowpacks in the dismal range of 40 to 60% of normal.
Many areas north of the Snake River Plain received above average precipitation and snowpacks increased up to 34 percent. March storms left the Panhandle snowpack at about 120% of normal. Snowpacks in the middle of Idaho range from 80 to 110% of normal. Streamflow forecasts rose due to the increased snowpack.
The abundant carry over water stored in Idaho reservoirs may be a problem in some areas that received abundant March precipitation. Reservoirs in southern Idaho are holding an above normal water supply and should accommodate the lower than normal runoff due to the low snowpack this year.
For more information about snowpack, precipitation, runoff and water supplies for specific basins, please view the complete April 2012 Water Supply Outlook Report online at www.id.nrcs.usda.gov/snow and click on the ‘Water Supply’ link.
NRCS conducts snow surveys at the end of each month from December through May to make snow runoff predictions and water supply forecasts used in managing Idaho’s water resources.