A few inches of snow and freezing temperatures brought Atlanta and much of the South to a near standstill Tuesday evening and Wednesday morning.
Traffic got so bad that people abandoned their cars and hundreds of kids slept over at their schools.
The city ended up looking like a scene from zombie apocalypse series "The Walking Dead."
Plenty of people in areas used to winter weather blamed the disaster on those who simply can't drive in snow, no matter how little.
But other factors were at play. We asked a couple of experts to explain just what really happened. The answers include improper planning, driving conditions that are bad even when the weather is good, and the use of sand instead of salt.
1. Bad Traffic Made Worse
Asked how the situation in Atlanta got so bad, Hibbett Neal, the international president of the Institute of Traffic Engineers, noted "the traffic's bad anyway."
According to the 2012 Annual Urban Mobility Report from the Texas A&M Transportation Institute, Atlanta's traffic is the seventh worst among the country's major metropolitan areas. The public transportation system is a mess, which discourages people from giving up driving. On average, commuters waste 51 hours a year stuck in traffic.
When Tuesday's storm hit in the early afternoon, the roads started to fill up. Larken McCord, a teacher in Atlanta, told Business Insider that most public schools did not stagger the release of their students — so they all had to be picked up at once. In general, she said, "there was not a whole lot of coordination."
In the aftermath, Georgia Governor Nathan Deal said it was clearly a mistake to release government workers and students at the same time, just as private workers were making their way home. The result was that just as conditions were getting bad, everyone was getting on the road.
2. Icy Conditions
The region was hit by more than snow. "They got a lot of ice," John Allin told Business Insider. Allin ran his own snow removal business for nearly 30 years, and now works as a consultant for municipalities and non-profits (such as colleges) who need help creating contingency plans for winter weather.
Ice is challenging for drivers everywhere, he said. Slippery conditions were made worse by the fact that Atlanta spreads sand and stone on roads, not salt. Salt helps melt ice; sand is just for improving traction. It's the less effective choice in general, Allin added: On a highway, after 10 or 15 cars drive over it, its effect is nullified.
The problem with salt is that it's only effective if it's kept dry. That's why northern municipalities build storage facilities to house enormous piles of the stuff. Why would Atlanta want to make that investment when snowstorms come every few years?
In contrast, "sand is very inexpensive" to buy and store. So it's the logical option.
3. Untreated Roads Lead To Accidents
Then there's the fact that the vast majority of roads weren't even treated with sand before the storm — and the traffic — descended.
The city "did treat priority routes before the storm," an official said. According to Atlanta's website, those routes included 200 miles of roadways, 40 bridges, 6 hospitals, and 16 police precincts.
But even if those were covered, lots of roads were left untouched. When McCord drove home, on a route that doesn't include major interstates, the roads "had not been treated at all," she said. A trip that usually takes under 20 minutes took two hours.
On icy roads, accidents piled up quickly. By Tuesday evening, local news station WSB-TV was reporting"hundreds of crashes all over town." The fact that plenty of people abandoned their cars and walked home made things even worse.
Take an area where traffic is always bad, then put even more cars on the road. Start adding accidents and gridlock is inevitable. "That's pretty much the gist of it," Neel said.
Once gridlock set in, treating and plowing roads became more difficult. "Snow plows can't clear it out" when they can't go anywhere, Neel said.
Preparing For The Future
Allin cautioned against piling on state and city officials, as well as residents, for mishandling the situation. "I don't think they're bad drivers," he said, or bad at plowing and treating roads. "They just don't get to practice it enough."
But while he said it's not a question of "incompetence," Allin acknowledged that planning was inadequate. In a situation where the protocol is unclear, "everybody does what they think is best," and a "mob mentality" sets in. Everyone rushes home, some get in accidents, everyone gets stuck.
So what's the best course of action going forward, to prepare for another storm a few years down the line? Atlanta and cities like it should "formulate a plan, have it in place, and have senior management aware of it," Allin said. That would "solve a fair amount of the anxiety."
But, he added, going through this once in a while isn't the end of the world. "Economically, suffering through it" may be the logical choice.
SEE ALSO: 26 Pictures From The Insane Traffic Jam That Has Atlanta Looking Like 'The Walking Dead'