Olympic National Park

Site information

• Official name: Olympic National Park
• Location: Northwest Washington State, United States
• Type: Natural
• Year of inscription: 1981

"Green" comes to mind when one hears the words Olympic National Park, but verdant rainforests are not the only habitat protected by this international treasure. In fact, Olympic Park is celebrated for its diversity. It includes over one hundred kilometers of pristine coastline that support some of the most biologically diverse rocky intertidal communities on the West Coast.

The high alpine is studded with glaciers. There are sixty active glaciers in Olympic National Park. Some of these glaciers are lowland glaciers, beginning at less than two thousand feet above sea level. This is the lowest latitude in the world where you can find glaciers at this altitude. But it is the forests that dominate Olympic. The park contains one of the last large tracts of intact old growth rainforest in the contiguous United States.

Both the forests and the glaciers are fed by rain. Over two hundred inches of precipitation a year falls in the higher elevations, more rain and snow than anywhere else in North America. Lowland forests receive about 120 inches, while some areas in the rain shadow of the mountains near Sequim, Washington, only receive twenty.

The isolation of the Olympic Peninsula, along with the variety of altitudes and precipitation within the park have led to a complexity of habitats that support a great diversity of plants and animals, including a number of endemic species found nowhere else. Old growth forests provide habitat for threatened and endangered species such as the northern spotted owl, (Strix occidentalis caurina) marbled murrelet (Brachyramphus marmoratus), and fisher (Martes pennanti). There are eleven major river systems originating in Olympic. These rivers provide excellent habitat for many species of anadromous fish, including all five types of Pacific salmon.

Archaeological evidence shows that Olympic National Park has been inhabited for at least twelve thousand years. Early inhabitants followed a hunter/gatherer lifestyle, evolving to a place-based maritime culture by about three thousand years ago. Eight different tribes live in the vicinity of Olympic National Park in the early twenty-first century.

History

The Olympic Mountains massif is an accretionary wedge formed by the subduction of the Juan De Fuca plate under the North American plate. Sedimentary shales and sandstones, along with pillow basalts from the ocean floor, were scraped off the Juan De Fuca Plate as it dived beneath the North American Plate and were attached (accreted) to the edge of the upper plate. This terrane is bounded by the Cascades to the south and Vancouver Island to the north, so a great deal of rock has been crammed into a relatively small corner. This helped to form the horseshoe shape of the Olympic Mountains. The intense pressure also caused folding and faulting, transforming some of the rock into metamorphic material, such as slate.

The subduction of the Juan de Fuca Plate under the North American Plate continues, causing the area to be very tectonically active. In 1700, a magnitude 9 earthquake shook the area. The potential still exists for earthquakes of that magnitude in the area. The Olympic Mountains are a prime example of a subduction complex.

The rock in the Olympic Mountains is fairly young, only forty to sixty million years old, laid down during the Eocene and Miocene epochs. The layering in the rocks is not caused as much by time as by faulting; the rock was broken up and folded during uplift. The uplift was created largely by the plate collision but augmented by rebound from the retreat of the Cordilleran ice sheet. The Cordilleran ice sheet reached its southern boundary in Olympic National Park, surrounding the mountains on three sides and carving the Juan de Fuca Strait and Puget Sound. A separate ice cap formed on the Olympic Mountains, rounding some peaks and carving others. Rivers fed from this ice carved deep valleys but were dammed by the Cordilleran ice sheet, creating fjord-type lakes. Icebergs broke off this ice sheet and floated far inland, dropping granite glacial erratics up to 3,500 feet up on the mountains. The Olympic ice cap descended at least four times. The existing glaciers were born only twenty-five hundred years ago and reached their maximum growth just two hundred years ago.

Erosion plays an important part in creating the landscape we see today. Great rivers carve deep valleys. Gravity plays an important part as the slow downhill flow of soil (solifluction), soil creep, and landslides continue to wear the mountains down at the same time they are being uplifted.

Significance

Olympic National Park is proving to be a superb laboratory for studying global climate change. Ongoing studies show dramatic changes in the park's glaciers. In 1982 there were 266 glaciers. By 2024, roughly 35 glaciers and 16 perennial snowfields had disappeared. Approximately 200 glaciers remained. If this rate of loss is left unchecked, Olympic National Park's glaciers could disappear by 2070. The rocky intertidal communities are another indicator of climate change. Park scientists are monitoring carbon dioxide levels and ocean acidification, correlating changes in ocean chemistry to changes in intertidal communities.

Another challenge brought on by climate change is warmer water temperatures, which threatens some keystone species. One example is starfish. A disease known as sea star wasting has reached epidemic proportions in starfish populations throughout the West Coast. Believed to be caused by a virus, outbreaks of the disease are closely tied to warmer water temperatures.

Olympic National Park is a leader in habitat restoration. The Elwha River was once one of the most productive fish habitats in North America outside Alaska. In the early twentieth century, dams were built on the Elwha for hydroelectric production, decimating the anadromous fish population. In order to bring the fish back, the Elwha River Ecosystem and Fisheries Restoration Act, passed in 1992, mandated the return of the Elwha River to its original state. One of the biggest restoration projects ever undertaken by the National Park Service, dam removal began in September 2011 with the Elwha Dam. The Glines Canyon Dam removal was completed in 2014. Restoration efforts such as revegetation and sediment flow studies are ongoing.

Olympic Bibliography

Cubley, E. S., and R. L. Brown. "Restoration of Hydrochory Following Dam Removal on the Elwha River, Washington." River Research and Applications, vol. 32, no. 7, Sept. 2016. doi:10.1002/rra.2999. Accessed 8 Dec. 2024.

Hewson, Ian, et al. "Densovirus Associated with Sea-Star Wasting Disease and Mass Mortality." Proceedings of the National Academy of Sciences of the United States of America, vol. 111, no. 48, Dec. 2014. doi:10.1073/pnas.1416625111. Accessed 8 Dec. 2024.

Lewis, Jeffery C., et al. "ts" Landscape-Scale Habitat Selection by Fishers Translocated to the Olympic Peninsula of Washington." Forest Ecology and Management, vol. 369, June 2016, 170–83. doi.org/10.1016/j.foreco.2016.02.032. Accessed 8 Dec. 2024.

."Olympic National Park's Glaciers Could Be Gone by 2070." AGU, 19 Apr. 2022, news.agu.org/press-release/olympic-national-parks-glaciers-could-be-gone-by-2070/. Accessed 8 Dec. 2024.