The reef at Pipe is a flat tabletop reef, with several caverns on the inside(middle of sonar data below), creating a giant air bubble that pops on the front of the wave when the wave lurches upwards just before breaking. There are also several jagged, underwater lava spires that can injure fallen surfers. Sometimes sand will fill the cracks in the reef at Pipeline that can cause waves to "close out" (meaning the hollow tube of the wave collapses all at once and thus is impossible to surf). A strong swell from the west clears out the sand in the reef and after that a strong north swell can give rise to the best waves for surfers to ride.

Echoscope® pipe line sonar imagery

Pipeline web Cam & surf Report

Rigging up the boat on the north shore