HONOLULU—For about a week, Hawaii's famous sunny weather has been replaced with thunderstorms, large pieces of hail, and the arrival of what weather officials say was the first tornado in four years to hit the islands.

The tornado formed as a waterspout offshore. After 7 a.m., it pushed more than a mile inland, tearing off part of a roof and carrying it several hundred yards through the coastal town and Honolulu suburb of Kailua. No one was injured.

A 30-minute hail storm Friday over windward Oahu was "unprecedented," for Hawaii, said Tom Birchard, senior meteorologist for the National Weather Service in Honolulu. Not only is it highly unusual for hail to fall over Hawaii, but some stones that measured as large as three inches are likely record-breaking, he said.