On a recent outing to the Wolfenstein boulder, Nancy, Nick, and I got to see what 15' NW groundswell looks like when it's split by the tip of Kaena Point and sent on its way down the west side of the island, toward, and then past, the Arch. It kind of looks like any other point break, but on a very large scale.
If there is seasonality to climbing in Hawaii, then this is it. Climbing at the arch, or any other coastal spot here, has everything do with how big the surf is. If you're a surfer, you pray for 15' NW groundswell. If you're a climber, you pray for flatness. If you do both, I guess you might feel conflicted on a day like this day.
The same storm that was making Rocky Mountain National Park too snowy and cold to climb produced this swell that was soaking the Arch. Waves were washing all the way up to the Arch's mauka base, the white foam covering the landing and sort of looking like that snow in Colorado.
About every 10-15 minutes a makeable-looking wave broke directly outside of the Arch. It was enormous, and maybe surfable with jet-ski assistance. The right outside the Arch is still a project.
Here are a few more pictures from that day.