He is talking about the Bitterroot River throughout Ravalli County and into Missoula County, the Clark Fork River and the Flathead River near Columbia Falls. Nickless believes these rivers will likely reach flood stage (if not over) this spring.
Flooding is not expected in Lake or Lincoln Counties this year unless we see a big rain event... nor on the St. Regis River but Flint Creek could experience minor flooding due to increased volume in Georgetown Lake.
As always, much depends on how much rain is received during the wet months of May and June. If a very wet system comes through with a lot of rain, high stream and river concerns will rise.
May and June are western Montana’s wettest months of the year with Missoula on average seeing 1.95" in May and 1.73" in June. Kalispell on average sees 2.04" in May and 2.30" in June.
The weather outlook for May is for below average temperatures and normal precipitation which could be a good thing because that could slowly melt the snowpack... key word: slowly. Currently the snow water equivalent (SWE) percent of normal is 187% for the Bittterroot Mountains. See the slideshow for a map of Montana and more SWE figures.
The outlook for June, July & August as a whole is for slightly warmer than average highs and normal precipitation.