CHICAGO — Thundersnow and whiteout conditions descended on Chicago Monday as the city was hit with yet another round of snow that could dump as much as 10 inches on some parts of the area.
The majority of the area received between 4 to 6 inches when the snow stopped around 6 p.m. Monday, meteorologist Jamie Enderlen said.
"Even though we might not have all the snow we [originally forecasted], it's still pretty awful out there for driving conditions," Enderlen said.
Traffic times skyrocketed around the area as Monday's blizzard severely limited visibility, causing whiteout conditions.
A jackknifed semi truck blocked traffic near the Circle Interchange Monday afternoon, state police said. Troopers were called to the scene about 3 p.m., but it had been cleared by 5:30 p.m.
More than 770 flights were canceled at O'Hare Airport, and more than 270 flights were canceled at Midway Airport, according to the city's Aviation Department. Delays were averaging about 45 minutes at O'Hare and were as long as two hours at Midway.
Thundersnow could be heard around the city Monday afternoon, sending people scrambling to Twitter to document the #thundersnow.
Enderlen said the National Weather Service recorded lightning "directly over Downtown" Monday afternoon, while some Hyde Park residents said they saw a single flash of lightning around 2:30 p.m., followed by a peal of thunder that faded over the lake as it rolled east.
The last time the city heard thundersnow, a fairly uncommon weather condition, was during the Groundhog Day Blizzard of 2011, National Weather Service meterologist Ben Deubelbeiss said.
Thundersnow happens when "we have what we call instability in the atmosphere," Deubelbeiss said.
That instability is created when warm air near the surface is situated near cooler air on top and "the tendency for that warm air to want to rise above the cool air," Deubelbeiss said. Thundersnow can result in heavy snowfall.
Across the city Monday, shoveling issues, fender-benders and traffic were common concerns.
In Englewood, Auburn Gresham and Chatham, traffic was moving at a sluggish pace as unplowed roads made it difficult to move, residents said. Neither main nor side streets had been cleared by 3:30 p.m.
Foot traffic was practically non-existent on Andersonville's Clark Street, despite business owners' best efforts to shovel snow. At Courtenay Elementary in Uptown, kids threw snowballs and played as they made their way to school buses.
Employees in Loop high-rises tweeted photos of whiteout conditions from their office windows. Many headed home early, and the CTA started rerouting buses at 1 p.m.
So far this winter, the city has recorded 62.1 inches of snow, which is 38.1 inches above normal for the season, according to the weather service.
It would take a total of 89.7 inches of snow to match the snowiest season on record set in the winter of 1978-1979.
The high temperature Monday is expected to be about 27 degrees, while on Tuesday and Wednesday, the high could reach about 38 degrees, according to the weather service.
On Thursday, temperatures could rise to 43 degrees.
Curious about thundersnow? Here is The Weather Channel's Jim Cantore reacting to the meteorological oddity during the Chicago blizzard of 2011: