Kobuk Valley National Park

Alaska · Established December 2, 1980

Arctic sand dunes and caribou crossings north of the Arctic Circle

Area: 1,750,716 acres
Established: December 2, 1980
Recreation visits: 7,786 / yr
State: Alaska
Highest point: Mount Angayukaqsraq, 4,760 ft (1,451 m)
Active sand dunes: About 20,500 acres in three dune fields

Kobuk Valley Weather Forecast

Loading the National Weather Service forecast for Kobuk Valley…

Seven-day outlook at the park's reference point (67.356, -159.200). Elevation changes everything in the mountains — expect colder, windier and wetter conditions on high ground.

Map of Kobuk Valley National Park

The Park

About 25 miles north of the Arctic Circle, in a broad valley between two ranges of the western Brooks Range country, lies one of the least expected sights in Alaska: rolling golden sand dunes, some of them rising as high as 100 feet. Kobuk Valley National Park protects these Ice Age dunes, a slow, braided stretch of the Kobuk River, and the ancient crossing where caribou have swum the river for thousands of years.

The park was established on December 2, 1980, and has no roads, trails, or visitor facilities inside its boundaries. Visitors arrive by bush plane or boat, often from the villages of the Kobuk River, and find a vast wilderness of boreal forest, tundra, and sand where people have hunted, fished, and traveled for at least nine thousand years.

Geography

Kobuk Valley covers 1,750,716 acres of northwestern Alaska. The Baird Mountains, part of the western Brooks Range, form its northern boundary, and the lower Waring Mountains rim it to the south. Between them the Kobuk River meanders westward across a wide lowland of spruce woodland, wetlands, and lakes toward Kotzebue Sound.

Rivers flowing south out of the Baird Mountains, such as the Salmon, Tutuksuk, Hunt, and Akillik, cross the valley to join the Kobuk. South of the river, on the flanks of the Waring Mountains, lie the park's three dune fields: the Great Kobuk Sand Dunes, the Little Kobuk Sand Dunes, and the Hunt River Dunes. Together they hold about 20,500 acres of active sand, the remnant of dune fields that once covered as much as 200,000 acres after the last glaciation.

Landmarks

Great Kobuk Sand DunesDuneThe largest active Arctic dune field in North America, with dunes rising up to about 100 feet.
Little Kobuk Sand DunesDuneA smaller dune field near the park's eastern edge, partly surrounded by forest.
Onion PortageAreaA bend of the Kobuk River where caribou cross and people have hunted them for thousands of years; a key archaeological site.
Mount AngayukaqsraqPeak · 4,760 ftThe park's highest summit, in the Baird Mountains, containing rocks more than a billion years old.
Salmon RiverRiverA clear, designated wild river flowing south from the Baird Mountains to the Kobuk.
Hunt RiverRiverA Baird Mountains tributary of the Kobuk, near which the Hunt River Dunes lie.
Akillik RiverRiverA mountain stream in the park's eastern section flowing toward the Kobuk River.
Tutuksuk RiverRiverA tributary draining the western Baird Mountains.
Ahnewetut CreekRiverA creek crossing the valley lowlands near the Great Kobuk Sand Dunes.

Geology

The mountains that frame Kobuk Valley are built from some of the oldest and most complex rocks in Alaska. In the Baird Mountains to the north lie metamorphosed sedimentary and igneous rocks, including those of Mount Angayukaqsraq that are more than a billion years old, along with the Ordovician to Devonian Baird Group and the Devonian to Mississippian Endicott Group. To the south, the Waring Mountains include the Angayucham assemblage, fragments of ancient ocean crust and volcanic rock, and younger Cretaceous sedimentary rocks. These pieces were thrust together when the Brooks Range formed during Mesozoic mountain building.

The park's most famous landscape is far younger. During the Pleistocene, glaciers grinding down from the surrounding mountains produced vast amounts of fine sand and silt. Meltwater carried this sediment into the Kobuk valley, and after the ice retreated, strong winds swept the exposed sediment into immense dune fields covering as much as 200,000 acres.

As the climate warmed and grew wetter, vegetation gradually stabilized most of the sand. Today, only about 20,500 acres remain active, mainly in the Great Kobuk Sand Dunes, where prevailing winds still reshape the ridges each year. Along the river, eroding bluffs expose layered Ice Age sediments, and the valley floor is shaped by permafrost, oxbow lakes, and the Kobuk's shifting meanders.

Deep time

More than 1 billion years agoThe oldest rocks of Mount Angayukaqsraq form, later metamorphosed.
Ordovician to DevonianMarine sediments that become the Baird Group accumulate.
Mississippian to Early JurassicOceanic volcanic and sedimentary rocks of the Angayucham assemblage form.
MesozoicMountain building thrusts rock slices together to form the Brooks Range.
PleistoceneGlaciers produce fine sand that washes into the Kobuk valley.
End of the last ice ageWinds build dune fields covering as much as 200,000 acres.
About 9,000 years ago to presentPeople hunt caribou at Onion Portage, while vegetation stabilizes most of the dunes.

The rocks

Mount Angayukaqsraq metamorphic rocksMore than 1 billion years
The park's oldest rocks, found in the Baird Mountains.
Baird GroupOrdovician to Devonian
Metamorphosed marine sedimentary rocks of the Baird Mountains.
Endicott GroupDevonian to Mississippian
Sedimentary rocks exposed in the northern part of the park.
Angayucham assemblageMississippian to Early Jurassic
Oceanic basalt and related rocks exposed in the southern part of the park.
Kobuk dune sandsPleistocene to present
Fine glacial sand and silt reworked by wind into active and stabilized dunes.

Trees, Plants & Ecosystems

401vascular plant species recorded

Boreal forest (taiga)Valley lowlands
White and black spruce with birch and poplar reach near their northern limit in the Kobuk valley.
TundraUplands and mountain slopes
Tussock cottongrass, dwarf shrubs, and lichens cover the treeless slopes, providing caribou forage.
Active sand dunesSouth of the Kobuk River
Sparse grasses and the endemic Kobuk locoweed grow on shifting sand that can heat up sharply in summer sun.
Riparian corridorsRivers and floodplains
Willow thickets and balsam poplar line gravel bars used by moose and bears.
Wetlands and lakesKobuk River lowlands
Oxbow lakes and bogs support nesting waterbirds, beaver, and northern pike.

Trees

White sprucePicea glaucaThe tallest conifer, growing on well-drained riverbanks near its northern limit.
Black sprucePicea marianaA slow-growing spruce of cold, poorly drained permafrost soils.
Alaska birchBetula neoalaskanaA white-barked birch of mixed forest on warmer slopes.
Balsam poplarPopulus balsamiferaFragrant trees along river floodplains and gravel bars.
Quaking aspenPopulus tremuloidesFound in small stands on dry, sunny slopes.
Feltleaf willowSalix alaxensisA tall willow of river bars and an important moose food.
Siberian alderAlnus viridisA shrubby alder forming thickets along streams and slopes.

Wildflowers, shrubs & other plants

Kobuk locoweedOxytropis kobukensisA purple-flowered legume found only on and near the Great Kobuk Sand Dunes.
Tussock cottongrassEriophorum vaginatumIts white cottony heads dot the tundra in early summer.
CloudberryRubus chamaemorusAn amber berry prized by local residents.
LingonberryVaccinium vitis-idaeaTart red berries on low evergreen shrubs.
Bog blueberryVaccinium uliginosumLate-summer berries relished by bears and birds.
Marsh Labrador teaLedum palustreAn aromatic shrub of bogs and spruce woodland.
Eightpetal mountain-avensDryas octopetalaA mat-forming plant of dry tundra with white flowers.
Arctic lupineLupinus arcticusBlue flower spikes on open slopes.
FireweedEpilobium angustifoliumMagenta flowers that bloom in burns and along rivers.
BearberryArctostaphylos uva-ursiA low shrub with red berries on sandy soils.
American dunegrassLeymus mollisA tough grass that helps anchor sand.
Altai fescueFestuca altaicaA bunchgrass of dry slopes and forest openings.

Wildlife

28mammals
109birds
16fish

Mammals

CaribouRangifer tarandusWestern Arctic herd caribou migrate through the park each spring and autumn, crossing the Kobuk River.
Brown bearUrsus arctosRoams the valley and mountains, feeding on berries, fish, and carrion.
American black bearUrsus americanusFound mainly in forested areas.
MooseAlces alcesBrowses willows along the Kobuk River and its tributaries.
Gray wolfCanis lupusPacks follow the caribou herds.
WolverineGulo guloA powerful scavenger of remote country.
Red foxVulpes vulpesHunts rodents in forest openings and tundra.
Canada lynxLynx canadensisA snowshoe hare specialist of the boreal forest.
MuskoxOvibos moschatusAn occasional visitor from herds in northwestern Alaska.
Arctic ground squirrelSpermophilus parryiiHibernates through the long winter in burrows.
Snowshoe hareLepus americanusTurns white in winter.
American beaverCastor canadensisActive in lowland ponds and sloughs.
Collared lemmingDicrostonyx groenlandicusThe only rodent that turns white in winter.
American minkMustela visonHunts along streams and lakeshores.

Birds

Golden eagleAquila chrysaetosNests on cliffs in the Baird Mountains.
GyrfalconFalco rusticolusThe world's largest falcon, a year-round Arctic resident.
Sandhill craneGrus canadensisNests in wetlands and calls loudly in summer.
Tundra swanCygnus columbianusNests on tundra lakes.
Pacific loonGavia pacificaBreeds on lowland lakes.
Willow ptarmiganLagopus lagopusAlaska's state bird, turning white in winter.
Rock ptarmiganLagopus mutusA ptarmigan of rocky upland tundra.
Northern wheatearOenanthe oenantheA small songbird that migrates between Arctic Alaska and Africa.
Arctic warblerPhylloscopus borealisNests in willow thickets and winters in Southeast Asia.
Arctic ternSterna paradisaeaMakes one of the longest migrations of any animal.
American golden-ploverPluvialis dominicaA striking shorebird nesting on tundra.
Lapland longspurCalcarius lapponicusOne of the most abundant tundra songbirds.
Common ravenCorvus coraxStays through the dark Arctic winter.
Canada jayPerisoreus canadensisA resident of spruce forests.

Fish

SheefishStenodus leucichthysA large whitefish, known as inconnu, prized by Kobuk River residents.
Chum salmonOncorhynchus ketaRuns up the Kobuk River in late summer.
Chinook salmonOncorhynchus tshawytschaA less common salmon in the Kobuk system.
Arctic graylingThymallus arcticusA sail-finned fish of clear tributaries.
Dolly VardenSalvelinus malmaA char of mountain streams.
Northern pikeEsox luciusA predator of lakes and sloughs.
Broad whitefishCoregonus nasusAn important subsistence fish.

Species totals are the park's certified NPSpecies checklist (occurrence: present).

Climate & When to Visit

Kobuk Valley has a harsh subarctic climate of long, bitter winters and short, surprisingly warm summers. In January, average lows are near -8°F and temperatures can drop to -50°F. Around the winter solstice the sun rises for only about an hour and a half. Summer brings the opposite extreme: the sun does not set from about June 3 to July 9, average temperatures are in the mid-60s °F, and highs can reach 85°F. Exposed sand on the dunes can become very hot on sunny days.

Weather can change quickly at any time of year. Snow, rain, and freezing temperatures are possible even in summer, and cold, wet, windy days can bring a real risk of hypothermia. Freeze-up of rivers and lakes usually begins in autumn, and snow covers the valley for much of the year. Summer also brings swarms of mosquitoes and biting flies, especially in wet lowlands.

Spring
Cold, snowy conditions persist into May; breakup opens the rivers and caribou move north toward their calving grounds.
Summer
Continuous daylight from early June to early July, average temperatures in the mid-60s °F, and heavy mosquito activity; the main season for visits.
Autumn
Tundra turns red and gold in late August and September as caribou migrate south across the Kobuk; snow can arrive early.
Winter
Long, dark, and extremely cold, with temperatures that can plunge to -50°F.

Weather hazards

Hypothermia: Cold rain and wind can be dangerous even in summer, so carry quality rain gear and warm layers.
Flight delays: Weather can ground bush planes for days, so pack extra food and plan flexible travel dates.
Cold, swift rivers: River water is cold, and capsizing can quickly become life-threatening.
Bear encounters: Carry bear spray, store food in bear-resistant containers, and camp away from trails and rivers used by bears.
Insects: Bring head nets and repellent for intense mosquito and biting fly activity in June and July.

Kobuk Valley Questions

When is the best time to visit Kobuk Valley National Park?

Most visitors come from June to early September, when rivers are open and planes can land on gravel bars and lakes. Late August and September bring autumn colors and the caribou migration, with fewer insects.

How do you get to Kobuk Valley National Park?

There are no roads to the park. Visitors typically fly from Kotzebue or nearby villages such as Kiana and Ambler on chartered bush planes, or travel by boat on the Kobuk River.

Why are there sand dunes in the Arctic?

During the last ice age, glaciers ground rock into fine sand that meltwater carried into the Kobuk valley. Winds then built huge dune fields, and about 20,500 acres of active dunes remain today.

What is the weather like at Kobuk Valley?

Summers are short and mild, averaging in the mid-60s °F with continuous daylight in June. Winters are long and very cold, with January lows averaging near -8°F and extremes down to -50°F.

Where can I see caribou?

Caribou of the Western Arctic herd pass through the park during spring and autumn migrations, often crossing the Kobuk River near Onion Portage. Timing varies from year to year.

What is Onion Portage?

Onion Portage is a bend in the Kobuk River where caribou cross and people have hunted them for about 9,000 years. It is one of the most important archaeological sites in the Arctic.

More parks in the Alaska

← Kenai Fjords National Park Lake Clark National Park & Preserve →

Sources: www.nps.gov · www.nps.gov · www.nps.gov · en.wikipedia.org · irmaservices.nps.gov · Official NPS site