Minecraft wiki entry for Things_not_to_do, associated text: The player should note that death is extremely rare from this kind of scenario; a close call is far more likely. Another note worth taking is to be careful near desert ravines, as there are sometimes overhangs of sand with no sandstone beneath them. These blocks fall as soon as they are updated by a player placing or breaking a block next to the sand. This can result in the sand falling away and dropping the player down large heights. Be careful when building in the desert if you think there might be a ravine nearby.