The accident occured just past the Thung Thong Police checkpoint in Kathu at aproximately 9.25am this morning.
According to an investigating traffic officer, the bus was overloaded and was unable to ascend the hill, as it rolled back down several meters, its back slipping off just over the road's edge before it finally came to a stop.
Indeed, the outcome could have been a lot worse.
At least 40 persons have been sent to Patong Hospital to be treated for injuries incurred from the accident.
Several other motorbike drivers have reported slippery conditions on the hill this morning.
Shortly after the initial accident, in the tailback down the hill another accident was reported, in which a truck's brakes allegedly failed before it rolled back down and collided with a white sedan directly behind it.
Commuters between Patong and Kathu should expect traffic delays the rest of the morning, and are urged to proceed with caution.