Abandoned vehicles sit on an exit of Interstate 285 Wednesday in Dunwoody, Ga. Around Atlanta, nearly all public entities and most businesses were shut down Wednesday, and officials encouraged would-be motorists not to drive.

ATLANTA — The snow and sleet have stopped falling and traffic was moving again around Atlanta following a crippling storm — but transportation and rescue officials said that didn’t mean it was safe yet to drive, especially after the sun goes down.

Officials from the Georgia Department of Transportation said Wednesday night that they were concerned with subfreezing overnight lows potentially leading to layers of black ice coating roads that might appear to be safe.

Although it was supposed to be in the high 30s today, it is forecast to dip below freezing again before rising into the 50s on Friday.

“Whatever little leeway that we’ve gained with melting and slushiness is gonna refreeze,” Georgia Department of Transportation spokesman Karlene Barron said of local road conditions. She added that the department was especially concerned with semi-trucks jackknifing and leading to additional traffic jams.

Heeding the warnings, school districts and state and local governments stretching from northwest to coastal Georgia announced that offices and classrooms would remain closed today.

A storm that dropped just inches of snow Tuesday wreaked havoc across much of the South, closing highways, grounding flights and contributing to at least a dozen deaths from traffic accidents and a mobile home fire. Yet it was Atlanta, home to major corporations and the world’s busiest airport, that was Exhibit A for how a Southern city could be sent reeling by winter weather that, in the North, might be no more than an inconvenience.

The Georgia State Patrol responded to more than 1,460 crashes between Tuesday morning and Wednesday evening, including two fatal crashes, and reported more than 175 injuries.

At Hartsfield-Jackson Atlanta International Airport, more than 400 flights in and out were canceled by 6 a.m. today, according to data from the flight tracking service FlightAware. Many of those flights were canceled before the day began.

Thousands of schoolchildren either slept on the buses that tried and failed to get them home, or on cots in school gymnasiums. All were back home by Wednesday evening, officials said.

State transportation crews spent much of Wednesday rescuing stranded drivers and moving disabled and abandoned vehicles that littered the interstates, medians and shoulders. Gov. Nathan Deal said emergency workers, police, and the National Guard would help drivers today to recover their cars and would provide them with fuel if necessary.