Record river flows end wet March for Montana
MISSOULA, Mont. - An unusually wet March means the rivers look like they've jumped ahead to the end of April in many parts of Montana. At least three area rivers set new March 30 stream flow records: the Big Hole River near Wisdom, the Yellowstone River near Livingston and the Gallatin River at Gallatin Gateway.
Average temperatures during March were a few degrees warmer than average, according to National Oceanic and Atmospheric Administration records. NOAA says that contributed to more loss of snowpack and an increase in stream flow. However, the real impact came from impressive precipitation.
According to the National Resources Conservation Service water basins in western Montana saw between 150 and 200 percent of normal moisture this month. Most of that is now working its way through our river system. Erosion from the rain and melting snow caused numerous problems with flooding and mudslides over the past couple of weeks.
Although Thursday's record flows are east of the divide, the amount of cubic feet per second in these rivers pales in comparison to what's coming down west of the divide. While the Gallatin River set a record with over 500 cfs, the Clark Fork near East Missoula was just below its record at over 5000 cfs. The Flathead River is also gushing to end the month, raising the water level in Flathead Lake by a foot between March 23 and March 29.
Meanwhile, NRCS data shows a healthy snowpack within 90 to 110 percent of normal for most areas. What does this mean? Our big spring runoff won't be early this year. Expect flows to peak in the normal months of April and May, likely thanks to the March moisture. However, this pattern of wet weather looks like it's going to keep right on going as we start April. If stream flows remain high when the runoff gets going, flooding in low-lying areas would be more likely than versus the past few years.