Karen is Dorothy's birth mother. She left her at Gales' farmhouse one stormy night and returned 20 years afterwards to reconnect with her daughter.
Karen lives in a trailer outside town. On the night Dorothy arrives to talk to her, she is attacked and seriously wounded.
Karen keeps weather monitoring equipment in her trailer and seems to be paying special attention to tornadoes. It was revealed in Episode Three that a woman apparently named K.Chapman was brought to the castle of the Mistress of the Eastern Wood by the Wizard himself in order to send her back from Oz.