The incident happened shortly after 2pm yesterday close to the Pineberry Inn.
Reader Andrew Lambert, who posted pictures of the incident on Twitter, described “blizzard conditions” and added that the accident meant there was “no way through”.
Mr Lambert said: “Lots of emergency services here. Drivers and passengers involved sheltering in a double decker bus. At least one stretcher used but all seem to be slow-speed minor bumps.”
A police spokesman confirmed 11 vehicles were involved but said there had been only one man with injuries which needed hospital treatment.
A snow plough and gritters were called in to help make the scene safe.
The road was closed in both directions to allow the vehicles to be recovered. It was re-opened at about 4pm.