The National Weather Service issued Sunday night a flood advisory for the Jefferson River near Three Forks due to an ice jam. On Monday, an ice jam was reported on the Gallatin River near Logan with minor flooding developing in the region, with mostly agricultural land near the river being impacted.
Dangerous ice jams and related flooding could result in these areas if temperatures warm up rapidly and send large pieces of ice downstream. Residents should be on alert for changing ice conditions when temperatures start to rise.
Ice jams are especially dangerous because they can occur quickly and without much warning. If an ice jam does occur, the National Weather Service advises the following:
Stay clear of the area. Flood waters can rise quickly, putting lives at risk.
Report any ice jams to local authorities.
Never walk out onto unstable river ice or drive through flood waters.
Michelle McNamee, a DNRC floodplain specialist, said that residents should prepare themselves and their property now for potential ice jam flooding.
Due to the unpredictable nature of ice jams, McNamee recommends residents 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.
Be ready to transport valuables or, where practical, elevate them.
According to the National Weather Service, Montana has the highest number of reported ice jams and ice jam-related deaths in the lower 48 states. Most of Montana's ice jams occur in February and 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.