What's the Name of That Book??? discussion

I read this in 1986 or 87. A family moves to Nantucket. I think the main character was a girl, but I'm not sure. She has an older sister in high school. She begins developing frightening elemental or nature based magic powers. She is guided in this by an old man. A main point in the story is when she gets really angry at her sister, who falls down some stairs and breaks her leg. This turns out not to be the girl's fault, but she blames her powers for it anyway.
Help?
Thanks!

There are elements of this that sound like A Gift of Magic.

A girl begins to develop magical abilities after she, her mom, older sister, and younger brother move to Florida (I think... It's certainly somewhere near the beach.). Her sister has the gift of dance, her brother has the gift of music, and she has the gift of magic.

Her sister is supposed to leave the family to go to dance school, but the girl doesn't want her to go, so she angrily wishes her sister would get hurt. Her sister falls down some stairs and breaks her leg. The girl's upset about it and hates her powers, but then she uses them to rescue her brother who has been swept out to sea.

It does sound a lot like it, except I'm certain it took place on Nantucket Island, not in Florida.

It's not Practical Magic? I haven't read the book, by Alice Hoffman, but the movie has some similarities.

Lauren, are you still looking for this or did you find it?

Lobstergirl wrote: "Lauren, are you still looking for this or did you find it?"

No response in 2 years. Moving to Abandoned.