As temperatures rise, officials watch for flooding, ice jams

As the suburbs slowly warm following last week’s bitter cold, weather experts say a mass snowmelt is unlikely, but those along waterways should keep an eye out for ice jams and potential flooding.

Scott Lincoln, senior service hydrologist at the National Weather Service in Chicago, said even if temperatures reach above freezing as expected, the snow will melt rather slowly.

“You'll see rivers kind of creep up, but that won't necessarily be a significant flood risk.” Lincoln said. “You usually need a really strong system bringing in a lot of warm air, and that is a little unusual in January just in general, let alone when you have this much snow.”

Lincoln said the bigger concern is ice jams along rivers and localized flooding that could result.

“That's probably the bigger threat for the next week,” he said. “We have a lot of ice in our area rivers, and while a lot of it is kind of starting to freeze in place because it's been so cold for so long, as we get a little bit of melting or get a little warmer that might cause some of the ice to shift.”

Ice jams, typically caused by melting snow and ice in the spring, occur when chunks of ice clump together to block the flow of a river.

Areas of concern along the Des Plaines River include Riverside and Lyons, where the NWS and the Cook County Department of Emergency Management are keeping in contact with local officials.

“While ice jams are less common on the Des Plaines River, they still have the ability to cause flash flooding in low lying areas along the river,” Natalia Derevyanny, spokesperson for Cook County’s Bureau of Administration, said in an email. “This flooding can occur with little to no notice and can be potentially dangerous.”

There have been no requests for support and no major impacts to critical infrastructure so far, Derevyanny added.

Further south, the NWS issued a flood warning effective Friday afternoon along the Kankakee River from near Kankakee upstream to near Sun River Terrace.

In Kane County, officials are watching for ice jams along the Fox River, but not yet concerned about system-wide flooding.

“It’s also important to understand that Kane County does not have a history of flooding caused by ice jams, at least not in the last decade or so,” Office of Emergency Management Director Scott Buziecki said in an email.

Lincoln advises those living near rivers to watch out for ice that looks jumbled up, broken or piling up. Another sign of a potential ice jam is the water level rising upstream of the jam.

While there are typically trained spotters on the job, Lincoln said the general public can alert the weather service if they see the river rapidly rising unexpectedly.

“That's the kind of stuff that's really important for us to know so that we can investigate what's going on and see if an ice jam might be causing flooding,” he said.

Whether they live near a waterway or not, homeowners concerned about damage from the melting snow can take steps to protect their property.

Erie Insurance recommends making sure downspouts are draining away from the house, checking for snow and debris that may be blocking roof gutters, and shoveling excess snow away from downspouts, basement window wells and stairwells.

Kevin Martin of the Illinois Insurance Association said safety should be the number priority.

“Take extreme caution no matter what you do this time of the year with trying to address snow and ice, because there's just so many potential serious problems that could develop,” Martin said. “I would suggest that people who don't have the ability to do it themselves reach out to a professional to come over and take care of it.”

Martin added the best way for homeowners to address potential build up in their drains and gutters is to tackle the problem ahead of snow and ice.

“Don't wait until the latter part of January or February to address it. It's something that should be part of home maintenance when you clean gutters out in September or October,” he said. “Take care of the gutters, take care of your downspouts, take care of how the water is draining away from your home — but do it in a month where the weather is much nicer and you can actually probably do a much better job.”

Jenny Whidden is a climate change and environment writer working with the Daily Herald through a partnership with Report For America supported by The Nature Conservancy. To help support her work with a tax-deductible donation, see dailyherald.com/rfa.