Weeks of subfreezing weather are giving way, at least briefly, to temperatures in the 40s and 50s, putting many Midwestern cities on guard for flooding, roof collapses and clogged storm drains. Some areas expected a double whammy: warm, spring-like air combined with heavy rains that could compound the problem and turn the big melt into a muddy, damaging mess.
A whole new layer of snow and sleet was forecast to accumulate early Thursday, particularly across Wisconsin, northern Illinois and parts of Indiana, before temperatures rise and change the precipitation to rain, according to the National Weather Service. The warmer temperatures may be accompanied by fog and strong winds that could reach 50 miles per hour.
Landscaping companies' phones were ringing off the hook Wednesday with calls from homeowners seeking crews to scoop snow piles onto dump trucks and haul them away before basements or streets flooded.
"They're calling me to say, 'With this rain coming, where is that water and the snow going to go when it melts?'" said Jodey Schmiedekamp of Countryside Industries in suburban Chicago.
Warnings were issued Wednesday that ice and deep snow could clog drainage systems. In Chicago, street crews were racing to clear catch basins of debris and asking residents to do the same.
Officials in Will County, south of Chicago, prepared to siphon warm water from a nuclear power plant's cooling pond into the Kankakee River in hopes of melting ice that can jam the channel and push floodwaters over the banks. At the same time, emergency management authorities warned people in low-lying areas to be ready to move to higher ground, even going door-to-door to ensure families were aware of the danger.
In Indiana, the weather service cautioned that melting snow piled as high as 18 inches wouldn't be able to flow normally into rivers and streams because those channels are frozen. Between the snowmelt and the rain, some flooding would be unavoidable.
"A lot of bad things could happen tomorrow," Marc Dahmer, a weather service meteorologist in Indianapolis, said Wednesday.
Parts of Michigan have gotten so much snow that authorities fret about more roof collapses like the one that injured two women Wednesday in the Grand Rapids area, which has received 101 inches of snow this season. Other collapses have been reported around the state since January.
If rain adds weight to the snowpack, it "can exacerbate the situation that's there," said John Maples, a weather service meteorologist in Grand Rapids.
And more good news: With temperatures expected to drop as low as 10 degrees on Sunday, and perhaps lower Monday, puddles along roads and sidewalks are expected to freeze.
The thaw may also reveal a struggle for survival that has played out all winter close to the frozen ground. As the ice and snow recedes around rivers, lakes and ponds, it could reveal dead fish, turtles, frogs, toads and crayfish that didn't make it.
"Winterkill begins with distressed fish gasping for air at holes in the ice and often ends with large numbers of dead fish that bloat as the water warms in early spring," said Gary Whelan, of the Michigan Department of Natural Resources.
After enduring so many snowstorms and painfully cold days, the people who emerged Wednesday in Chicago were delighted by sunshine and warmth that let them indulge in the simple pleasure of a walk or a jog.
"I should be in my office doing something, but I haven't been out there in three to four months," said Ning Du, 40, as she returned from a run along Lake Michigan in Chicago.
A block away, Caroline Vickrey and her friend Michelle Hoppe Villegas couldn't get past the change in people that seemed to reflect the change in the weather.
"Everybody is smiling and saying hello to each other," Vickrey said.
"My daughter was cheerful this morning (and) so pleasant," added Hoppe Villegas. "I was wondering what is going on here."