Residents along Wisconsin Creek near Sheridan might have got a surprise last Wednesday as the creek level, already swollen by snowmelt, suddenly got much higher prompting officials to warn local residents that a backcountry dam may have failed.
With water rising rapidly, it was clear something had happened in the headwaters of Wisconsin Creek, said Steve DiGiovanna, communications director with Madison County.
“We had to go with that idea until we proved otherwise,” DiGiovanna said.
The rising water prompted an emergency response by local volunteer fire departments and officials who warned residents along the creek that water was rising rapidly and for an as yet unknown reason.
One of the inhibiting factors to ascertaining the exact cause of the rising water was the extreme gusty wind last Wednesday and impending darkness, DiGiovanna said. So officials had to wait until Thursday to fly into the Tobacco Root Mountains at the head of Wisconsin Creek to see what had happened.
The problem seemed to be with Noble Creek Reservoir, which feeds Noble Creek – a tributary of Wisconsin Creek, DiGiovanna said.
Though there was still too much snow on Thursday to see exactly what happened, it appeared that snow may have been blocking the spillway on the backcountry dam and that when the water in the reservoir rose enough it suddenly broke through, releasing a large volume of water, he said.
The initial push of water started to recede by late in the day Wednesday, but the stream is still high and causing problems, DiGiovanna said.
The push of water nearly destroyed a culvert bridge about seven miles up Wisconsin Creek off of Montana Highway 287, he said. The road in that location is closed.
One of the more interesting results of the high water is that Wisconsin Creek is finding channels that it likely hasn’t used in years, he said. Some of them have probably never seen water as high as it is now.
Other creeks out of the Tobacco Roots are running high as well, including Indian Creek and Mill Creek, DiGiovanna said.
“They’re all drainages out of the Tobacco Roots that are loaded with mountain snow,” he said.
The National Weather Service has a flooding warning out for northwest Madison County through Thursday evening.
“Continuing snow melt will keep water levels high on both Wisconsin and Indian Creeks at locations around Sheridan and Twin Bridges,” reads the warning. “Other small creeks and streams within the county will also continue to run high and fast. Some locations continue to see some minor flooding. Those driving along Highway 287 from Ennis to Twin Bridges should be prepared for possible flooding with water flowing over roadways.”
The good news is that the creek levels seem to be on the drop, DiGiovanna said. However, people still need to be cautious.
“They’re still high and they’re flowing well, but they’re under control right now,” he said. “Be aware that streams and rivers and creeks can rise rapidly.”