Only a week or two of warm weather and an increased level of rainfall has sharply reduced the snowpack in the mountains of Montana, including the Bitterroot Valley. Lucas Zukiewicz, Natural Resources Conservation Service (NRCS) water supply specialist, said the last week of May and the first week in June "were game changers." In a news release this week, he said eastern Montana was most affected with an accelerated early melt. Areas with reservoirs will be in better shape in late season water supply, but "on free-flowing river systems there could be implications later this summer."

In western Montana, snowpack levels in the Kootenai, Flathead and Lower Clark Fork Rivers are above normal, with the Lower Clark Fork at 151 percent of normal. Missoula has been experiencing some flooding. On the other hand, the Bitterroot snowpack is now only 46 percent of normal for this time of year. One of the reasons - precipitation in the last few weeks was 136 percent above normal for the Bitterroot. Summer streamflow forecasts are now slightly below normal, according to the NRCS.