Now is time to prepare for ice jams, flooding

By Star Staff

Nearly half of ice jams that occur east of the continental divide occur in the month of March, so now is the time to begin preparing for them. The cold and snowy 2017-2018 winter has resulted in favorable conditions for ice jams and their associated flooding.

There are different types of ice jams that can occur, according to a news release from the National Oceanic and Atmospheric Administration. Freeze-up ice jams occur when prolonged subfreezing weather allows an ice cover to develop on a river or stream. Break-up jams occur when the freezing weather is followed by significant warming, allowing the ice on rivers to break free and flow downstream.

Jams typically form as ice accumulates at obstacles such as bends in rivers or bridge supports. Water can quickly back up behind the jam and cause flooding.

Jams also can release very quickly, often causing flash flooding as the water stored behind the jam then rushes downstream. Snowmelt or rain on snow and the breakup of river ice often occur in tandem and can result in more intense flooding.

While many ice jams develop and release before causing significant flooding, some can produce extensive flooding and cause considerable damage. It’s important for people with interests along area rivers to be aware of this threat. Now is the time to prepare, before the threat becomes imminent, moving equipment and livestock to higher ground.

When river ice begins to break, it’s important to stay away and move to higher ground. Low lying areas can quickly become inundated with flood water and ice within a matter of minutes. With the upcoming flood season quickly approaching, it’s important that any flood insurance be purchased early. In most cases, flood insurance does not take effect until 30 days after purchase.

Anyone who sees an ice jam is urged to contact the local National Weather Service office, the county Emergency Manager or local law enforcement.