Point Grenville is a headland with cliffs 120 feet (37 m) high, about 2.5 miles (4 km) north of the community of Santiago, on the Quinault Nation lands in Washington State. Among the oldest rocks along the coast form most of Point Grenville and the nearby offshore sea stacks in the Copalis National Wildlife Refuge. The volcanic rocks are submarine lava flows that were ejected onto the seafloor about 45 to 50 million years ago during the middle Eocene. In other places, very fine-grained, dark-colored basalt was formed. All the volcanic materials were shattered into small angular fragments, and these rocks are now welded together forming a volcanic breccia.
On July 12, 1775, Bruno de Hezeta, Juan Perez, and others from the Spanish ship Santiago landed on the shore of the wide bay south of Point Grenville and claim Nueva Galicia (the Pacific Northwest) for Spain. This was the first European landing on the coast of the future Washington State. The point was named Punta de Los Mártires (Point of the Martyrs) in response to an attack by the local Quinault Natives. From 1949 to 1979, the U.S. Coast Guard operated a LORAN-A radio navigation station at Point Grenville. The point is considered sacred by the Quinault and is now the site of the Quinault Nations’ Haynisisoos Park.
Point Grenville is known for green flash sightings, an optical phenomenon that occurs under certain meteorological conditions just after sunset on the west coast. Green flashes are best observed from locations with an unobstructed ocean horizon such as capes and headlands. The phenomenon is explained by the scattering of sunlight through the atmosphere when the sun is just below the horizon so that the distance light travels through the atmosphere to the observer’s eye is maximized. All the colors of light are preferentially scattered, and the only remaining wavelength corresponds to green light. When the conditions are right, with a clear and still atmosphere, a distinct green spot is briefly visible above the upper rim of the Sun’s disk. The green light usually lasts for no more than a second or two. Read more here and here. Explore more of Point Grenville here: