Ice jams cause flooding, chaos amid arctic outbreak

The Captain JP Morgan crashes into an AMTRAK bridge along the Hudson River in New York on January 25, 2019. (Photo: New York State Police)

As if icy roads and stinging winds that could cause frostbite in the matter of minutes weren’t bad enough, there’s another problem resulting from the lingering record-breaking arctic outbreak across the Great Lakes region – flooding caused by ice jams.

It’s become so cold that some rivers are starting to freeze over. Pieces of floating ice carried with a stream’s current can accumulate at any obstruction to the stream flow. These ice jams can develop near river bends, mouths of tributaries, points where the river slope decreases, downstream of dams, and upstream of bridges or obstructions. The water that is held back by the jams may cause flooding or flash flooding upstream, and the water can move swiftly. If the obstruction suddenly breaks, then flash flooding may occur downstream.

Ice jams can disrupt transportation, as they did along New York’s Hudson River last Friday morning. The ice forced several vessels, including an unoccupied cruise ship, to break free from their moorings and float away. According to a report from Fox News, it happened during morning rush hour, and, as a precaution, the New York State Police was forced to close several bridges between Troy and Albany as the boats drifted south. One boat crashed into an Amtrak bridge; two U.S. Coast Guard ice-breaking cutters and two commercial tug boats eventually pulled the boat free.

The National Weather Service (NWS) office in Chicago tweeted earlier this week that there would be a potential for ice jams and flooding any day this week in its County Warning Area (CWA) because of the prolonged period of extreme cold weather in the forecast. The Cleveland, Ohio office tweeted a similar statement the same day.

Flood Warnings, first issued on Tuesday, continue today (Wednesday) for some areas along the Kankakee River in Illinois and Indiana because of reported flooding due to ice jams. These are details from this morning’s update:

• The Flood Warning continues for the Kankakee River at Momence, from the Illinois-Indiana state line downstream to the confluence with the Iroquois River at Aroma Park.
• At 7:45 a.m. today the stage was 6.5 feet and was ice-affected.
• Flood stage is 5.0 feet.
• Moderate flooding is occurring and moderate flooding is forecast.
• Forecast is for the river to remain above flood stage for the next several days.

Flood Advisories, less urgent that Flood Warnings, have been posted for areas along the Rock River in southern Wisconsin and northern Illinois where water levels have been receding. But with the potential for more ice jams forming, the river can rise again with little or no warning. This could also be an issue along the Fox River between Yorkville and Oswego, Illinois. Trained weather spotters continued to report an ice jam on Tuesday near Saw Wee Kee Park just downstream of Oswego where minor flooding was occurring.

Ice jam flooding can be very localized and not affect all locations along the river as in a typical river flood. However, those who live in low-lying, flood-prone areas should remain alert for possible flooding due to ice jams. Find the latest flood alerts and winter weather alerts on this interactive map. Temperatures across many portions of the Great Lakes should warm significantly this weekend, relative to the current cold.

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Nick Austin, Director of Weather Analytics and Senior Meteorologist

In his 17 years of weather forecasting experience, Nick worked on air at WBBJ-TV and WRCB-TV, including time spent doing weather analysis and field reporting. He received his Bachelor of Science in Meteorology from Florida State University as well as a Bachelor of Science in Management from Georgia Institute of Technology. Nick is also a member of the American Meteorological Society and National Weather Association. As a member of the weather team at WBBJ-TV in Jackson, Tennessee, Nick was nominated for a Mid-South Emmy for live coverage of a major tornado outbreak in 2008. As part of the weather team at WRCB-TV in Chattanooga, Tennessee, Nick shared the Chattanooga Times-Free Press Best of the Best award for “Best Weather Team” for eight consecutive years. Nick earned his National Weather Association Broadcasting Seal in 2005.