Rare rainfall means high flow on Kootenai |
| June 21, 2013 |
|
A rare, extreme rainfall pattern developed over
the Kootenai and upper Columbia basins during
the last two days. Managers at Libby Dam have
increased outflow and are working to regulate
for extreme conditions. Twenty four hour rainfall totals were impressive; from one to six inches. Greater amounts (~10") were seen near the Continental Divide. The circulation of air and uncommon track of an upper level low with moisture mainly from the east, combined with moisture from the Pacific, to produce this heavy rainfall event. The rainfall is winding down today, with drier weather forecast Saturday. The precipitation totals in the basin above Libby Dam were four to six inches on June 20. For relational value; in June of 2012 the basin above Libby Dam had six inches for the entire month, which was extremely high for a monthly total in June. "Today we expect to see a peak inflow of 90 kcfs or higher," said Joel Finolio, U.S. Army Corps of Engineers. "Base flow conditions earlier this week were 30 kcfs of inflow to Koocanusa Reservoir. "Yesterday we increased releases from 16 kcfs to powerhouse capacity of 25 kcfs, once we saw the precipitation in Idaho and Montana drop off, to control the refill rate of Koocanusa Reservoir. "We will start to spill three kcfs this evening and plan to do so through the weekend to save space for any potential rainstorms through the first part of July." |