The runway is designated 14/32, oriented roughly northwest-southeast along the beach in Grays Harbor County. Its surface is sand -- not gravel, not compacted earth, but the same tidal sand that beachcombers walk on and waves reshape twice a day. The usable length was originally 4,500 feet by 150 feet wide, but river migration and beach erosion have shortened it by approximately 1,100 feet. The Copalis River, which bounds the southern end, has been slowly shifting its mouth, eating into the runway from one side while the Pacific gnaws from the other. Pilots who land here learn to read the beach the way sailors read the water -- checking for soft spots, debris, driftwood logs rolled in by storms, and the firmness of the sand at different points in the tidal cycle.

Before S16 became an official airport, the beach served military purposes. During the 1940s, this stretch of coast was part of the Grays Harbor Army Base, one of several coastal defense installations built along the Pacific Northwest shoreline during World War II, when the threat of Japanese attack was real -- submarine I-25 shelled Fort Stevens in Oregon and bombed forests near Brookings in 1942. Grays Harbor County first established the airport in 1951, formalizing what military pilots and local aviators had already been doing. The state took over management, and in 1976 it was designated as a state airport. For the 12-month period ending May 2011, the airport recorded about 200 general aviation operations -- roughly 16 landings or takeoffs per month, a modest number that reflects both the airport's remoteness and its tidal constraints.

Copalis State Airport sits within the North Beach Seashore Conservation Area, adjacent to the Olympic Coast National Marine Sanctuary -- one of the richest marine ecosystems on the Pacific coast. The juxtaposition is striking: an active runway, however intermittent, sharing geography with a federally protected marine sanctuary. Gray whales migrate past in spring and fall. Bald eagles patrol the tideline. Razor clams burrow in the same sand that airplane wheels compress on approach. The airport's existence within this conservation area is a kind of negotiated truce between human use and natural preservation, one that works precisely because the ocean enforces its own schedule. No one builds hangars on a beach that floods twice a day. No one paves a runway the tide will dissolve.

There is something clarifying about an airport that the ocean can erase. Pilots who fly into S16 must plan around tide charts, not just wind and weather. A late departure means no runway to return to. A miscalculated approach puts wheels into surf rather than sand. The experience strips away the infrastructure that makes most aviation feel routine -- the concrete, the taxiways, the tower frequencies -- and replaces it with something older: a flat stretch of earth, the sound of the Pacific, and a window of time that the moon controls. It is flying reduced to its essentials, and for the pilots who seek it out, that is precisely the point. The beach will be here tomorrow, and it will be an airport again, but only when the tide says so.