The Roundup -

Potential for Ice Jams and Related Flooding Greatest in February and March


Damaging floods caused by ice jams are a fact of life along many Montana rivers and streams. With warmer conditions expected this week, the Montana Department of Natural Resources and Conservation (DNRC) would like to remind residents that the heavy ice covers on waterways could break apart in some areas, producing prime conditions for ice jams and associated flooding.

“Montana experiences the highest number of reported ice jams in the continental US, with most occurring in February and March” said DNRC Director John Tubbs. “Flooding can happen in any community and it can happen quickly. Residents in flood-prone areas should take steps to safeguard their families and property.”

Ada Montague, a water resource planner with DNRC, said the National Weather Service has advised that temperatures around the state are expected to rise above freezing from Jan. 24-26, with rain also expected in some areas. Potential impacts from melting snow and rainfall include pooling of water in areas where storm drains or ditches are clogged with snow and ice, pooling of water in low-lying areas, and potential ice jams on small creeks.

Michelle Phillips, a DNRC floodplain specialist, said it’s important that residents living near a river or stream have a flood evacuation plan and consider the following steps:

• Purchase flood insurance. In most cases flood insurance must be purchased 30 days before a flooding event.

• Keep extra drinking water on hand. Flooding can compromise local water systems.

• Shovel or plow snow away from homes and structures.

• Be ready to transport valuables or, where practical, elevate them.

The Montana All-Hazards Weather Monitor web site offers up-to-date information on stream flows and potential flood conditions:

To learn more about the National Flood Insurance Program, visit

More than 80 percent of ice jams and associated flooding in Montana take place between January and March, with the highest number occurring in March. The most ice jams ever recorded in a single season was 75 in 1996. In more recent years, 2004 saw 40 ice jams, 2006 produced 14, and 23 were recorded in 2011.


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