How Did This Mind-Numbing Chinese Traffic Jam Even Happen?

Traffic in China is among the worst in the world, but honestly, I have no clue how a blocked intersection like this even happens.

This cameraphone picture, taken in Xi'an, Shaanxi province, uploaded to Weibo last Wednesday, shows perhaps the most amazingly blocked intersection I've ever seen. The uploader gave the following caption.

How Did This Mind-Numbing Chinese Traffic Jam Even Happen?

Yanta West Road and Suzaku Road Interchange. Blocked [exhausted emoji]

Shanghaiist points out that Weibo users (like the Chinese version of Twitter and Facebook rolled into one) call this "Mahjong Gridlock."

Heavy rain made regular traffic go from bad to worse, but even that doesn't fully explain how sixteen buses end up perfectly closing a four-way forty-lane intersection. How did the people in the middle get trapped in there? How the hell did they get out?

Photo Credit: Weibo via ChinaCarTimes