March Madness For Idaho's Water Supply

Apr 10, 2012

Hydrologists from the Natural Resources Conservation Service call the latest snow survey results "March Madness in Idaho."  Storm after storm hit the state in March, marking one of the greatest one-month changes in snowpack on record. 

Warm weather melted the snowpack in Bear, Blackfoot, Bruneau, Owyhee, and Portneuf basins.  Some of those basins have what NRCS calls a “dismal” snowpack of 40 to 60 percent of normal.  But in other areas, like the Wood and Lost basins, snowpack levels jumped 16 to 34 percent in March.  The Panhandle snowpack was at 120 percent of normal.  Hydrologists say that all of this evens out, meaning most of Idaho now has an average snowpack for the start of April.

Higher than average snowpack isn’t all good news.  Too much snow means a higher potential for flooding as the weather warms up.  Hydrologists warn streams are already full, and soil is saturated from record precipitation across much of Idaho. 

This means any additional rain storms will quickly produce runoff. People living in flood prone areas should keep one eye on the sky, and another on the National Weather Service.  Reservoirs are filling up.  The Magic, Little Wood and Mackay combined are 160 percent of average.   The Boise and Payette systems are 127 percent of normal and are already releasing very high flows.