Large trees that have burned off under grown or at the base fall on a regular basis now. Ash pits are something to constantly be aware of as sometimes they look like normal ash covered ground but when you step on them you can go deep and break a leg very easily.
Wind blown ash fills them in with light fluffy ash and they are in reality a hidden danger. It is hard to walk in the woods looking for a large tree that is burned off at the base and only held in place by a thin margin or splinter of wood. You have to be looking around and down at the same time.