City snow plows are turning their attention to side streets early Tuesday after a heavy snowfall and “thundersnow” Monday made this season the city’s fifth-snowiest winter.
The city’s Department of Streets and Sanitation redeployed its full fleet of more than 310 snow plows and salt spreaders to side and residential streets early Tuesday, according to a statement from spokeswoman Molly Poppe. The fleet had originally been deployed Monday morning to keep Lake Shore Drive and arterial roads clear as the snow fell.
Thunder crackled as snow fell at Navy Pier about 3 p.m., at the beginning of an especially challenging evening rush hour, according to the National Weather Service.
“All of the expressways have been a mess today,” weather service meteorologist Eric Lenning told the Chicago Sun-Times. “All afternoon they have been in pretty bad shape.’’
Quick-falling, heavy snow reduced visibility to as little as an eighth of a mile in some areas and turned roadways slushy and slick.
By 6 p.m., O’Hare International Airport had recorded 4.7 inches of snow for the day, bringing the season’s total to 66.8 inches. That pushed this season past the winter of 1951-1952 for the fifth snowiest on record, Lenning said. The next target: the winter of 1966-67, which saw 68.4 inches.
More than 770 flights were canceled at O’Hare and 270 were scratched at Midway International Airport as snow fell at a rate of 2 to 3 inches an hour.
Temperatures were predicted to rise above freezing, with highs in the upper 30s Tuesday and Wednesday, then dip back down to freezing overnight, with lows in the upper 20s.
That should create an “ideal melting situation,’’ meteorologist Jamie Enderlen said, and could cause flooding.
On Thursday, temperatures could jump to a high of 43.
Snow already on the ground contains 1 to 4 inches of water, with the highest totals near the Wisconsin state line. The melting snow and rain may have no place to go because the moisture can’t soak into the frozen ground, according to the weather service. Instead, water will flow into rivers, and that could cause runoffs and flooding.
There is also a risk for an ice jam, which starts when ice breaks into blocks that collide with each other. Ice jamming can lead to significant increases in water levels and flooding, according to the weather service.
The weather service hasn’t issued a flood warning yet, but meteorologists are monitoring updates from the river forecast center.
City workers have cleared catch basins — openings on the sides of streets that drain excess water — to prevent flooding and give water a place to filter. If litter settles in a catch basin, water can’t reach the sewer.
Department of Water Management spokesman Tom LaPorte suggests that Chicago residents help drainage by raking litter out of basins near their homes so that water can flow into sewers.
“Rainblockers,” which keep water in the streets and gradually send it to sewers, are also part of catch basins on many Chicago streets, LaPorte said.
During a rainy season, rainblockers help water enter sewers, but trash clogging the blockers delays drainage. If water is in the street for a few hours, the rainblocker is probably working properly, LaPorte said. If the street is flooded with water for more than a few hours though, LaPorte suggests calling 311.