This is o portion of the North Fork of the Teto 



following the June, 1964 flood. 



I Photo by U. S. Forest Service) 



The Centennial Flood 



During 1964, the year of Montana's Terri- 

 torial Centennial, a June flood devastated the 

 state from northern Lewis and Clark County 

 to Glacier Park on both sides of the Continental 

 Divide. This, the largest flood ever recorded 

 for the area, resulted from rainfall which ap- 

 proached the theoretical amount possible for 

 a given period. It came at a time when the 

 streams were already full with water from 

 melting snow. Sixteen inches of rain fell in 

 36 hours in one area. Water swept down the 

 Flathead, Marias, Teton, Sun, Dearborn and 

 other rivers taking 34 lives, leaving thousands 

 homeless, and causing damage in excess of 

 60 million dollars.' 



Concern was expressed for fish in the flood 

 area. It con be assumed that newly hatched 

 fish-of-the-year in flood streams fared badly 

 and that some older fish were killed from va- 

 rious causes such as being stranded. No doubt, 



I A complete report on the flood will be published by the 

 U. S. Geological Survey os o woter supply paper. 



stream scouring played havoc with trout food 

 insects which dwell on stream bottoms. 



Fish, however, have for eons survived re- 

 peated onslaughts of nature — too much water, 

 too little water, and temperature extremes dur- 

 ing crucial periods. Losses of year classes and 

 other catastrophies are common to fish popu- 

 lations. Due to the tremendous reproductive 

 capacity of fish — an average female trout lays 

 1,500 eggs annually — the loss of a year class 

 is only a minor disaster and even decimated 

 fish populations soon recover. Consequently, 

 after the 1964 flood, fishing soon returned to 

 normal except on those streams where the 

 necessary environment for fish survival and 

 reproduction was destroyed. 



Destruction of stream channels was the real 

 cause for concern, for if basic fish habitat is 

 destroyed or partly destroyed, the carrying ca- 

 pacity for fish is lost. Some streams were hit 

 much harder than other. The Middle Fork of 

 the Flathead River and its tributaries, Sun River 

 and its tributaries, Dearborn River and Teton 

 River were badly damaged as were Cut Bank, 



11 



