Nakahalele Blowhole on Maui's north coast is a sure crowd-pleaser—who doesn't like to see whitewater exploding 50 feet and higher from an opening in the reef?—but visitors are advised to stay back at risk of serious injury or death. That warning should seem obvious to all but the yahoos among us. But what is not obvious is to stay back and also stay away from the ocean side of the sea geyser, since sleeper waves can jump the reef and knock bystanders for a loop.
Two trails lead down to this well-known, but unmarked roadside attraction, the longer of which is the most scenic (at mile marker 38) since a melange of colorful geology is thrown in to the mix. A half-mile farther, the second trailhead, from which the blowhole is visible, is a switchback down a steep embankment. Several of the trails along this undeveloped coast see few tourists; Maui Trailblazer has more details.