If driving in the Twin Cities was bad Tuesday night, a fresh round of snow Wednesday will probably make it even worse.

Several inches fell Tuesday on top of day-old ice, tripling and quadrupling drive times.

And more is on the way. After some drizzle during the day, 4 to 6 inches is expected by Wednesday night with flurries continuing well into Thursday.

Road conditions are expected to be dangerous — and maddeningly slow — as the new snow piles on top of the snow and ice.

“Extra time is the phrase of the day,” Minnesota Department of Transportation spokesman Kevin Gutknecht said Tuesday.

Motorists sat through major delays Tuesday evening, when most Metro Transit buses were behind schedule by an average of 30 minutes and Google maps predicted a two-hour slog from the State Capitol to Minneapolis’ North Loop via Interstate 94.

Snow totals varied across the metro area, ranging from 3 inches in Minneapolis to nearly 8 inches in Northfield, where the district called off classes for Wednesday.

With road conditions deteriorating, Minneapolis Public Schools canceled all after-school activities and athletic events for the second straight day Tuesday. In St. Paul, schools that normally dismiss at 2 p.m. let out a half-hour early to allow more time for buses to make their rounds and “help reduce delays” for late afternoon runs, the district said.

Meanwhile, a plane slid off the runway at the Mankato Regional Airport while trying to take off Tuesday. No one was injured.

On Monday, Regions Hospital in St. Paul treated 93 patients for ice-related injuries, including many head traumas.

Snow-covered sidewalks may be the most treacherous place to be, said Brent Hewett, a meteorologist with the National Weather Service in Chanhassen.

“The ice will still be there,” he said. “Untreated surfaces will be covered with snow. If you are walking, you might not expect ice, and there is the risk to slip and fall.”

Icy conditions are thought to be at fault for a two-vehicle crash in Blue Earth County that killed Matthew S. Ulmen, 44, of Mankato on Monday.

City, county and state agencies prepared for the snowfall Tuesday by dispatching an armada of plows and applying salt. But with temperatures in the single digits above zero, chemicals don’t work as well and icy spots will persist, Gutknecht said.

Crews were able to remove ice on many county roads and heavily traveled city streets before Tuesday’s snow began falling. But side streets remained in “poor condition” and will likely stay that way until warmer weather arrives, said Mike Kennedy of the Minneapolis Public Works Department.

Back-to-back storms prompted the Minnesota Department of Public Safety to warn drivers to carry a survival kit in case they become stranded.

This week the Minnesota Department of Transportation reported that 25 of its plows have been hit and put out a plea for drivers to give them room to work.

“The safest place you can be is well behind the snowplow and away from the snow cloud it creates,” said Todd Stevens, acting state maintenance engineer. “The road is clear behind the plow but not necessarily in front of it.”

The Twin Cities has seen about 17.6 inches of snow for the season, far below the normal of 35.5 inches by Feb. 5, the weather service said.

Temperatures will struggle to reach above zero Friday. Some places will see the mercury dip to 15 below on Saturday morning.

“We are going to jump back in a hole,” Hewett said. “But it won’t be anything like last week.”

Staff writer Liz Sawyer contributed to this report.