Lyn Allison grabbed his camera phone to capture a shot of sand spouting in front of the Outrigger Waikiki hotel Tuesday.
Beachgoers watched in awe, confused by the unexpected eruption.
"All of sudden we see a twirling of the sands and I just thought maybe it was wind tunnel; something like that," said Allison.
Washington visitor Julie Snyder barely escaped being caught in the mini sand storm.
Moments earlier, Snyder walked away from her beach chair, which lined up directly over the sand geyser.
"My chair was completely engulfed in sand and everything was totally covered. It was nuts," said Snyder.
The state said engineers were testing a sand conveyance pipe buried roughly three feet below, when the pipe sprung a leak.
The tests are part of the state's project to extend the beaches along Waikiki.
The break happened just as crews are beginning to pump sand offshore Waikiki back to the beach.
Contractors are dredging 24,000 cubic yards of sand from the ocean floor. The sand will be pumped through a pipe into a basin, before being spread across the beach.
The state said crews are trying out method before the sand pumping process begins.
Back on the beach, visitors say the excitement of seeing Hawaii's version of Old Faithful was still sinking in.
"I need more than one Mai Tai. Make it a double or two," Snyder joked.
The state said crews will weld the broken pipe on Wednesday and continue testing.