Grass-covered ground bordering or within a bunker is not part of the bunker. The margin of a bunker extends vertically downwards, but not upwards. A ball is in a bunker when it lies in or any part of it touches the bunker. A hole made by a non-burrowing animal, such as a dog, is not an abnormal ground condition unless marked or declared as ground under repair. Snow and natural ice, other than frost, are either casual water or loose impediments, at the option of the player.
Manufactured ice is an obstruction.
Dew and frost are not casual water. A ball is in casual water when it lies in or any part of it touches the casual water. Neither is partner of the other. Equipment includes a golf cart, whether or not motorised. It shall be circular in cross-section.