Sand Dunes in the Arctic

By Hillary Hoppock
September/October 2018

One of the least visited U.S. national parks, Kobuk Valley National Park in Alaska is remote and wild, and known for its magnificent sand dunes. 

Just over 55 kilometers north of the Arctic Circle, Alaska’s Kobuk Valley National Park hosts a desert environment of sand dunes soaring 100 feet in the air, with recorded summer temperatures of 38 degrees Celsius.

The Great Kobuk Sand Dunes are relics of the last Ice Age. They rise unexpectedly out of the trees along the Kobuk River, along with their smaller counterparts, Little Kobuk Sand Dunes and Hunt River Dunes. Together, they form nearly 78 square kilometers of the largest active dune field in the Arctic.

This sea of sand formed 14,000 years ago as the continental glaciers covering much of North America retreated. The massive chunks of ice churned and ground the underlying rocks into great stretches of fine sand. Over time, the wind lifted the sand into the air and deposited it into the sheltered Kobuk Valley, creating over 80,000 hectares of rolling sand dunes along the banks of the Kobuk River. Vegetation has both encroached and been buried by the sand dunes repeatedly in the thousands of years of its existence. However, for the last 80 to 100 years, vegetation has reclaimed all but 6,500 hectares of the sand, as sparse grasses stabilize the sand, giving way to mosses and shrubs before the forest takes root.

Kobuk Valley National Park is one of the most remote and least visited national parks in the United States. Basically inaccessible except by foot, aircraft or authorized air taxis, a backcountry excursion into this largest high-latitude dune field leads to where visitors can’t see the edge of dunes and could be tricked into imagining themselves in Africa’s Sahara Desert.

The park is home to a rich variety of Arctic animals, rare plants, birds and waterways abundant in fish. Twice a year, 250,000 caribou make their annual migration across the dunes of the Kobuk Valley.

Archaeological sites in the park reveal at least 12,000 years of human occupation, primarily on the fish-filled banks of the Kobuk River, but also along the unique landscape edging the sand dunes. Here, the Inupiaq Eskimo continue to hunt caribou as their ancestors have for 10,000 years.

A Unique Environment
No glaciers currently exist within Kobuk Valley National Park’s area of nearly 690,000 hectares. The glacial outwash streams that emptied into what was a large lake in the Kobuk Valley 150,000 years ago became the slow-moving Kobuk River. Sheefish, a type of whitefish, are plentiful in the Kobuk River, where the call of a journeying sandhill crane can be heard.

Surprisingly, the dunes themselves are the water source for the riverside forest and wetlands. The desert’s dry sandy surface disguises water-saturated sediments beneath, fed by water percolating into the dunes and coming to the surface in extensive wetlands stretching north and east of the dunes.

The Great Kobuk Sand Dunes, which at 65 square kilometers comprises the lion’s share of the dune complex, exhibits the complete sequence of dune development. The U-shaped, concave dunes of its vegetative eastern portion give way to the crescent-shaped, unvegetated dunes in the western portion, with sand ridges drifting up to 100 feet in height.

Life on the Dunes
The active dunes cover approximately 8,300 hectares in the park. Most of the original dune fields is now vegetated by tundra and boreal forests of spruce, alder and birch trees. Sparse grasses, sedges, wild rye and even the occasional wildflowers, including the Kobuk locoweed that only blooms on the slopes of the Great Kobuk Sand Dunes, anchor in the sandy soil to support a luxuriant ground cover of lichens, mosses and algae adjacent to the woodland forest.

Along the edges of the Great Kobuk Sand Dunes, it is common to see tracks and other signs of animal passage. Footprints of black and grizzly bears, moose, porcupines and Dall sheep are found in the soft desert sand alongside wolf and fox dens. Every year, millions of birds also flock to Kobuk Valley National Park to breed.

The park lies astride the major migration route of the Western Arctic Caribou. Every spring, a herd of one quarter million caribou crosses from its winter area south of the park to reach its calving ground to the north along the Arctic coastal plain. Caribou hoofprints are found again in the fall as the herd returns southward through the park, which is part of its rutting area, to reach its winter area. This makes Kobuk Valley home to one of the last great migrations on Earth.

Visiting the Park
Visiting Kobuk Valley National Park is an extraordinary experience that requires careful preparation for a backcountry excursion, coupled with an awareness and respect for native inholdings and local subsistence practices.

The 10-year average of visitors for 2003 to 2012 was 5,260, but their web presence has increased actual visitation in the last five years. The Kobuk Valley National Park website, www.nps.gov/kova/planyourvisit/index.htm, offers tips and suggestions on planning a visit to the park.

Hillary Hoppock is a freelance writer, former newspaper publisher and reporter based in Orinda, California.