Mary Pope Osborne - High Tide In Hawaii

Book 28 in the Magic Tree House series (2003)
A novel by Mary Pope Osborne
When the Magic Tree House whisks Jack and Annie off to Hawaii it's for more than a vacation-they're in search of a fourth kind of magic for Morgan! On the way they help an island community survive a tidal wave and, of course, take some time out to surf! Ultimately, they discover that the magic that they have found in this set of four books are everyday magics: the magic of the arts, the magic of the natural world, the magic of community; and the magic of fun.