This Impossible Brightness by Jessica Bryant Klagman

After the mysterious disappearance of her fiancé, Alma Hughes moves to a remote island in the North Atlantic, where she hopes to weather her grief and nurture her ailing dog. But the strange town of Violette has mysteries as well.

Townsfolk say that the radio tower overlooking their town broadcasts messages through their home appliances, their dreams, even the sea itself. When lightning strikes the tower, illuminating the sky in a brilliant flash, Alma finds herself caught in the unexplainable aftermath of one of Violette’s deadliest storms.

As the sea consumes the island, threatening its very existence, the deaths and lost memories of the recently departed also devastate the community. Alma, with a unique link to the lost, may be the only one who can help them move on. But to do so, she must confront a tragic loss of her own.