A blowhole is a hole in the ground connected to an underwater ocean cave and when conditions, like tide levels, are just right, a stream of air and water are forced out of the hole like a jet.  Now, to many the blowhole at Waianapanapa doesn’t appear to be very active.  It’s true that often it only sprays out small amounts of water or a fine mist.  However, don’t ignore the warnings to stay back, and definitely don’t look down into the blowhole.  When the blowhole actually sprays at full power, the best outcome will be a thorough soaking, and at worst serious injury is possible. Check with Hana Picnic Co for more information and directions.