It seems witches meet a nasty end, one way or the other.

The Wicked Witch of the East was crushed by Dorothy's farmhouse…

Though it can be argued that her other self, Nessarose, died when she stole Boq's heart and realized exactly who she was.

The Wicked Witch of the West was melted by a bucket of water thrown by Dorothy…

Her other self, Elphaba, died when Fiyero disappeared and she consequently showed her true self to all of Oz.

The Good Witch of the North is very much alive…but Glinda died when Elphaba did.