Residents in Twin Bridges and Ennis were still under a flood warning Tuesday night as cold temperatures persisted across Madison County and both the Madison and Beaverhead Rivers were clogged with ice.
Last week residents in Twin Bridges dealt with flooding in a handful of homes along Bridge Street, at Jessen Park and at the Madison County Fairgrounds as ice jams caused the Beaverhead River to top its banks and levies protecting the town.
At the same time, ice gorging in the Madison River near Ennis pushed water into overflow channels east of the river. One of the overflow channels flooded U.S. Highway 287.
Though the flood waters receded during the middle and end of the week, the cold weather that started Sunday brought them back up again, this time causing more problems around Ennis as highway 287 was closed intermittently Monday.
“I wouldn’t say that things are going perfectly but right now we’re holding our own,” said Steve DiGiovanna, Madison County Communications Coordinator, on Monday in reference to the situation in Twin Bridges.
In response to the flooding Twin Bridges declared an emergency, as did Madison County. As of Tuesday night, Ennis hadn’t declared an emergency.
The emergency declaration will allow both Twin Bridges and Madison County to tax residents up to two mills to offset emergency costs related to the flooding, said Chris Mumme, Madison County Department of Emergency Services director.
However, just because both the town and county have the authority to tax residents two mills, doesn’t mean they will necessarily use it, Mumme said. It is simply the process local governments have to go through in responding to funding emergency situations.
If the situation were to exceed the ability of the county to offset the costs with the two mills, then the county commissioners could ask the governor to declare an emergency, which would open up more funds, he said.
And though the situations in both Ennis and Twin Bridges were stable Tuesday evening, doesn’t mean the flood danger had passed, DiGiovanna said.
In both towns, officials are closely monitoring the situation, he said.
Ironically, this all comes as Montana is set to observe a state wide ice jam awareness day on Friday, said Gina Loss, senior hydrologist with the National Weather Service in Great Falls.
Ice jams like on the Beaverhead and Madison Rivers are common around Montana, Loss said. However, normally they don’t cause the flooding.
On both rivers, the ice started forming with the cold weather in November, she said. But unlike other years, Montana hasn’t seen very many warm days between then and now.
Couple that with river levels that are a little higher than in recent years and you have a recipe for more severe ice jams.
When ice forms in the river, it begins to collect on anything that would collect other debris – shorelines, bridge piers, fallen trees and rocks. As more and more ice collects, the water in the river struggles to stay in its channel and begins to rise, Loss said.
For instance, in Twin Bridges last Monday night and early Tuesday morning the Beaverhead River rose six feet in six hours.
The ice jams can dramatically alter the shape and look of a river due to the pressure and erosive power of all the chunks of ice being pushed along by the constant flow of water, she said.
From a safety standpoint, ice jams are incredibly dangerous because they are unpredictable and dynamic, Loss said.
“It’s never as stable as it looks,” she said. “I caution people to stay away from the ice.”
Even though the ice in the river or along its banks may appear stable, the pressure of the water flowing beneath it or near it is constant and could move the ice at any time, Loss said.
“It may appear incredibly serene but there are all kinds of dynamics you may not be aware of,” she said.
People should always stay well back of river ice and ranchers should do what they can to keep animals out of frozen river channels.
Another dynamic of ice jams is the rapid rise of water levels, either in the river channel itself or in side channels near the river.
At a meeting Tuesday morning, Madison County Sheriff Dave Schenk talked some about how fast the water flowing over Highway 287 rose in the afternoon. At one point Schenk was driving over the flooded portion of the highway and could almost see the water rising.
Montana Department of Transportation crews worked to find ways to get the water off the road and the water level lowered and as of Tuesday evening, the river seemed to be cooperating.
Also in Ennis, the town is broadcasting emergency information on 1610 am, which is a local, low bandwidth radio station.
Residents along Second and Third Streets are asked to be prepared for the river rising rapidly as long as the cold weather persists. If an emergency situation presents itself, the town will sound the air siren.
For updated emergency information, look on the Madison County’s emergency management website: www.madison.homestead.com.