Hurricane Diane — Jeanyne Johnson

In the third book in the series, Hurricane Diane, thirteen-year-old Ashley finds a note from her Nana who knows she can time travel. Her Nana wants Ashley to go back to 1955 to help save her cousin, Barb, who drowned during a flooding at a summer camp. Ashley hasn't quite figured out all the specifics of time travel, but when it happens, she must hurry. Hurricane Diane has dropped a tremendous amount of water, and there is flooding everywhere. If she can't convince them to get to higher ground, they could all drown. How will she save them? Can she fulfill her Nana's wishes and save Barb? What will happen to Ashley and her family if she somehow saves Barb but not Nana? This time, there is no room for error. Ashley's very life depends on her successfully saving her Nana.