Those who guessed surfing, hang gliding, skydiving, sailing, mountain biking, ziplining, kite boarding, windsurfing, kayaking, bodysurfing, deep sea fishing, or hiking jungly ridges or volcanoes are all wrong.
The most dangerous activity in Hawaii is beachcombing. Yes, walking along seashore minding your own business is when you are most likely (though still highly unlikely) to become injured or bite the big one while on vacation in the Aloha State.
Waves are the primary culprit. Higher waves mean a wider lethal 'impact zone' on the beach and on coastal bluffs and reefs. An increase in wave height also means a stronger rip current. The Hawaiian Islands are small specks of earth surrounded by thousands of miles of deep blue sea. Their shorelines are nuanced, each beach unique, making the conditions hard to read.
The good news is that you are in absolutley no danger if you keep an eye on the ocean and stay well back during high surf. The wet zone in the above photo would be a danger zone, during higher surf. You want to stay on dry sand.
Hazard signs are posted at the entrance to virtually every beach. People tend to ignore them, especially since many of the dangers are not present on most days. Every beach has safe days and days when caution is warranted.
Atlhough this dude is watching the surf, here at the far end of Lumahai Beach, he is in a position where he will need to run like hell when a rogue wave breaches the rock. Normally, people get in trouble when walking in the wet zone during high surf days. A larger wave comes and swamps them to the knees or waist, and, while they are struggling with the back-surge of the receding wave, the next one comes along and finishes the job. People are also swept off rocks by waves and surging swells. Doesn't matter if you are Michael Phelps.
People who read and heed the safety tips in Trailblazer Travelbooks are far less likely to be harmed while on vacation. The tips also cover hiking, surfing, snorkeling, and biking. And these are not merely blanket cautions, but the specific dangers associated with specific places. It's not the big stuff like hurricanes and volcanoes that reek havoc, but the little things that visitors aren't aware of.