Tignagvik Point is a headland on the western shore of Cook Inlet, marking the northern side of the entrance to Kamishak Bay, roughly 80 miles (129 km) west-southwest of Homer and about 47 miles (76 km) southeast of Iliamna, Alaska. The Alutiiq name was first published in 1915 by the U.S. Coast and Geodetic Survey. On the point’s north side lies Rocky Cove, a shallow embayment about 1 mile (1.6 km) across. The cove was named in 1903 by George C. Martin, a petroleum geologist with the U.S. Geological Survey who began investigating Alaska’s oil prospects that year and mapped much of the surrounding Cook Inlet coastline.

Waves erode coastal rock into nearly level shore platforms, whose width is governed mainly by tidal range and by how deep wave energy reaches. Wind generates surface waves, so stronger winds produce larger, more energetic ones; big waves can strike at any time of year but are most common in winter. Wave energy fades quickly with depth, and below roughly 33 feet (10 m) most of it has dissipated, so platforms rarely form deeper than that. Kamishak Bay, in the southern part of Cook Inlet, is exposed to strong winds and swell, and its wave-cut platforms are often visible at low tide. Local tides there run roughly 15 to 20 feet (4.6 to 6 m), large by global standards but well short of the roughly 30-foot (9-m) tides recorded far to the north near Anchorage, where Cook Inlet’s funnel shape and resonance produce some of the largest tidal ranges in North America.

Though shore platforms are erosional features, on the time scale that matters to benthic algae and animals, months to years, they behave as stable habitat and support dense algal growth. Biomass peaks in late summer, then declines as winter storm waves damage or dislodge the plants. Ice floes carried by Cook Inlet’s currents scour the rock further, stripping away all but the hardiest organisms and leaving bare surfaces that algal spores and animal larvae recolonize the following spring. Even so, this is a punishing environment: repeated tidal exposure, powerful wave action, and abrasive winter ice mean only the most tenacious species can establish a lasting foothold, and much of the platform’s community must effectively rebuild itself each year. Read more here andhere. Explore more of Tignagvik Point and Rocky Cove here: