What’s the Deal With: Those holey rocks on Whatcom and Skagit beaches?

The distinct honeycomb weathering starts when salt water meets porous rock, such as sandstone. George Mustoe, a research associate at Western Washington University and pioneer of honeycomb weathering research, explains that “as the salty solution dries, the growing salt crystals exert really strong forces to wedge apart the mineral grains,” creating small cavities.