By Ann McCreary
Andrew Denham, Twisp’s public works director, was keeping a close watch early this week on ice that has built up on the Twisp River, hoping to avoid a repeat of last year’s ice dams that that threatened to flood parts of Twisp.
The recent prolonged spell of frigid temperatures has produced thick ice on sections of the Twisp River, which could cause problems if it breaks free and moves downriver toward town.
“I drove upstream today,” Denham said Tuesday morning (Jan. 17), when temperatures were moderating somewhat. “It’s starting to slowly melt.”
Denham said he is watching for cracks in the river ice that could indicate a chunk is ready to break away.
“A big sheet can come down, and bring more ice with it,” Denham said.
That’s just what happened about the same time last year, when huge chunks of ice flowed downriver and choked off the water flow near the Twisp River Bridge at Highway 20, and near the Twisp River Ponds just west of town.
The ice dams broke open on their own before any flooding occurred, but Denham is prepared to take action if a similar event happens this year.
He has obtained an emergency hydraulic project permit from the Washington Department of Fish and Wildlife (WDFW), which would allow town officials to use heavy equipment to break up the ice to prevent flooding.
“In the event we have an ice dam, that [permit] will save us several hours if not a day. It allows us to do work on the ice from the bank with equipment” such as bulldozers or backhoes, Denham said.
Predicted warming temperatures early this week raised concerns that the ice could begin melting and breaking up, Denham said. If that happened quickly and releases the ice suddenly, it could create problems, he said.
“Anything can happen. There are so many variables,” he said.
The main area of concern is the portion of Twisp River that flows under the Highway 20 Bridge and makes a 90-degree turn by the town park.
Last January ice got jammed in that bottleneck and plugged the flow of water, which began backing up and rising, until the ice dam broke open and released the water.