Ice jams on rivers may pose problems as temps warm

Posted at 9:02 PM, Jan 31, 2019
and last updated 2019-02-01 09:48:01-05

WEST MICHIGAN — It may be hard to imagine temperatures in the 30s after being caught under the grip of the polar vortex this week. In fact, highs will rise into the 40s and perhaps low 50s by the beginning of next week. Problem is? That may come with issues on area rivers and their basins.

We’ve already seen a major ice jam blocking water along the Muskegon River at Newaygo. As of Thursday night, the river at that location is in MODERATE flood stage and could get worse. Take a look at the hydrograph for that location below. A hydrograph is a way of “graphing” the flow of water on a river in a given location.

Late Tuesday/early Wednesday the river stage was about eight feet high. After the ice jam, the level of the river almost doubled to it’s current level of 14.5 feet. That’s almost a 100 percent increase in height! On the right side of the graph is the flow in kcfs or a thousand cubic feet per second. Before the jam the flow was about 2,000 cubic feet per second. Afterwards…an almost 400 percent increase in flow to 10,000 cubic feet per second.

My conversations with the National Weather Service bring up big concerns about more of this happening next week. The Grand River basin may see a rise of two to four feet, while the Kalamazoo basin may be on the order of one to three feet. Most basins are in a position to take the upcoming snowmelt and rain that falls, but it’s the significant (and almost immediate) warm up that will jar the ice free and potentially cause more jams.

I know from previous years and similar situations that ice jams can/do cause rapid fluctuations in water levels within hours…sometimes minutes. That’s the real concern as we warm going in to next week. If you’d like to be linked to more of these hydrographs for area rivers, click here.

Take a look at the high resolution MODIS satellite image below of Michigan. One week ago there was little/no ice on the Great Lakes. Now, ice extends at least a few miles out in western Lake Michigan from Chicago/Milwaukee and up to Green Bay. In fact, much of Green Bay is frozen over as is Saginaw Bay. The Straits of Mackinaw are also frozen. Note the “lines” that run from the lake inland. Those are lake effect clouds and snow showers.

Make sure to stay up on later forecasts…especially if you live along a major river basin. Get the complete West Michigan forecast at