Montana Rivers Peak, Late Season Moisture May Curtail Fire Season

By Lucia Stewart, 6-27-08

It’s the weekend to get out and enjoy the rivers, as they’ve reached their max and the weather is going to be 80’s-90’sF and sunny across Montana.

To many of us, it seems like an amazing year of river flows, but not so.

“This is historically a normal year in Montana,” said Mel White, chief of the data management unit for the USGS in Helena. “We have just forgotten about what normal is because we’ve had a drought in effect for at least the past seven to eight years.”

Because of the unusually high snowpack along with the timely late May and June rains, the rivers have continued to rise up to this point. White concluded they have peaked and starting on their way down. Normal years sees peak flows in mid-to-late May.

“It’s a good thing,” said White. “Due to the increase moisture in the high country, it will keep the fisheries happy and curtails our fire season.”

Generalizing for the whole state, Montana sat at 90-109 percent of average snowfall all winter.

The Clark Fork running through Missoula usually sees mean late-June flows at 12,000 cubic feet per second (cfs), but is currently flowing at 21,100cfs.

One of the most significant flows of the season is on the East Gallatin near Bozeman, where its normal daily discharge mean is 269cfs. It peaked on May 25th at discharge of 1,860cfs, almost seven times its normal flow.

The Yellowstone River has also seen high flows, slumping and sagging the 9th Street bridge in Livingston, forcing its closer and stranding residents.

“It isn’t quite the 100 year floods on the Yellowstone River as we saw in 1996 and 1997,” said White. Those years, the Yellowstone River peaked around 37,000cfs, but only reached 27,500cfs this season.

For the USGS Montana real-time streamflows, click here.