The Oregon Dunes, the largest expanses of temperate coastal sand dunes in the world, stretch 40 miles along the Oregon coast between Florence and Coos Bay. They rise nearly 500 feet above the ocean and were designated a National Recreation Area in 1972.

Imported European beachgrass has created a foredune along the ocean. Behind it, winds create a deflation plain, scouring sand down to the water table and providing tiny oases for plants and animals. Transverse dunes, or ripples on the dune surfaces, are created by shifting summer winds. The largest dunes, called oblique dunes, can be as tall as 180 feet and move inland three to 16 feet each year. Parabola dunes interact with the surrounding forest, sometimes losing ground to the trees, sometimes smothering them, and sometimes leaving pockets of forest called tree islands.

We headed toward the dunes on the John Dellenback Dunes Trail near Eel Creek Campground. The trail meanders about one half-mile through lush rhododendrons, madrone and pines before opening onto the oblique dunes.

A brief rain the night before stabilized the sand and gave us good footing as we climbed to the ridge of the highest dune. We wandered along its curving edge about a mile toward a tree island. If you continue another couple of miles, you can hike all the way to the beach.

We saw shorebirds wading and feeding in pockets of water in the deflation plain, as fog rolled in over the trees at the edges of the dunes.

On our way back, we saw red fescue, described as “globally significant” and in need of protection. Signage notes that, although individual red fescue plants are common, “95 percent of red fescue communities are gone,” lost to competition from invading plants, like European beachgrass.