Branches fall from gum trees, particularly on stormy days. If they hit you on the head it will hurt. Gorges, by definition, have very steep sides often forming vertical cliffs. If you walk over the edge of a cliff it will hurt. Snow can fall at ANY time of the year in alpine areas.
Snow is very cold.
Ocean waves are unpredictable. It is very hard to stay standing when you're being hit by a tonne of water moving at speed. There are no street signs on every tree. If you don't know where you're going you can get lost. Be prepared, and get over it when it happens.