May And June Rainfall Will Help Montana Streamflows
While the hot weather has increased the snowmelt in Montana's mountains, May rainstorms (and even some more snow) is helping streamflow forecasts for the rest of the hot weather season in the state.
The monthly report from the Natural Resources Conservation Service (NRCS) in Bozeman reported two storms in May brought precipitation records to the Seeley Lake and Lincoln areas, and the National Weather Service reported the wettest May in Montana since 2018 and 15th wettest year on record. That helps in a year when the snow at mid- to low-elevation levels melted out weeks ago, ahead of the usual schedule.
Mage Hultstrand of the NRCS said some areas were left out to dry, however, including the northeastern Beartooths and Central Montana. HultStrand, a Water Supply Specialist, said snowpack peaked above average in the Upper Bitterroot, Upper Clark Fork and the Bighorn Mountains, which will cause good summer streamflow. Of course, more rain in June will help the stream health situation for both irrigation and recreation.
The rapid melting of the snowpack continues to worry experts in the Jefferson and Madison River basins, even though the rainfall was welcome. The earlier spring dry periods in have created a large "water year deficit." On the other hand, forecasters are expecting near normal streamflow for Gallatin and Yellowstone Rivers.
High water levels are beginning to drop with only minor flooding this season, such as the Clark Fork River at Missoula. The Bitterroot River almost reached the 11-foot flood stage at the USGS gauge near Victor last week, but has since receded a bit. The rivers and streams are still running fast and cold, so be aware and be careful.