Mount Olomana Viewpoint. The falls form where the bottom drops out of a mountain stream draining the rainforest on the lush Hamakua Coast. Thousands of gallons of water per minute pour over the edge of the cliff, plunging 442 feet in a single, spectacular drop, and crashing into the dark pool below in a fearsome ball of exploding white water. It's not the tallest waterfall in Hawaii (that would be 2,953-foot Oloupena Falls on the north shore of Molokai), but it is the tallest Hawaiian waterfall plunging from top to bottom in a single, unbroken drop, without cascading over ledges along the way.
There's a little shelter at the overlook where you can duck out of the rain, which can exceed 250 inches per year on this part of the island. Of course, the more it rains, the mightier the falls flow.