SEASIDE PARK, N.J. — On Thursday, as a raging fire erupted on a newly rebuilt boardwalk in two shore resort towns, some makeshift sand dunes saved part of it.

The fire that broke out near a frozen custard stand in Seaside Park rapidly spread north into neighboring Seaside Heights, the former home of MTV’s “Jersey Shore” reality show. With a stiff wind whipping the flames and driving them from block to block, the rest of the iconic boardwalk was in danger of going up in flames.

So Seaside Heights officials ripped out a 25-foot swath of the boardwalk and filled the void with giant sand piles — makeshift dunes designed to halt the spreads of flames and save the northern portion of the boardwalk.

“That appears to have done the trick,” Seaside Park Mayor Robert Matthies said.

The blaze destroyed all 32 businesses on the Seaside Park portion of the boardwalk. More than 20 other boardwalk businesses in Seaside Heights also were burned.