A reality based independent journal of observation & analysis, serving the Flathead Valley & Montana since 2006. © James Conner.
At 1000 this morning, Flathead Lake reached 2892.87 on the USGS Gage at Polson. This lake level amounts to de facto, or operational full pool. The license for Kerr Dam allows the lake be raised to 2893, but no higher, and as a practical matter, the lake is kept two or three inches below 2893.
Since April, 1938, Kerr Dam, on the Flathead River below Polson, has regulated the elevation of Flathead Lake. Since October, 1951, Hungry Horse Dam on the South Fork Flathead River has regulated approximately one-third of the inflow to Flathead Lake.
From 1952 through 2014, the lake has risen above 2893.10 just 16 times in the approximately 5,700 days of the summer boating season, nine times during the flood of 1964, six during the flood of 1974, and once in 1990.
Below are graphs displaying the historical norms for the elevation of Flathead Lake, and the history of the lake’s level on 15 June.
