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Grand Teton National Park

Wyoming · Established February 26, 1929

The Rockies' youngest range, rising sheer from the sage of Jackson Hole

Area: 310,044 acres
Established: February 26, 1929
Recreation visits: 3,800,648 / yr
State: Wyoming
Established: February 26, 1929; enlarged to include Jackson Hole in 1950
Area: 310,044 acres (1,255 km²)

Grand Teton Weather Forecast

Loading the National Weather Service forecast for Grand Teton…

Seven-day outlook at the park's reference point (43.819, -110.706). Elevation changes everything in the mountains — expect colder, windier and wetter conditions on high ground.

Map of Grand Teton National Park

The Park

The Teton Range has no foothills. Its peaks leap straight up from the flat sagebrush floor of Jackson Hole, more than 7,000 ft in a single sweep, their gneiss faces streaked with dark dikes and cupped by small glaciers. It is among the most photographed mountain fronts in America and one of the youngest ranges in the Rockies.

Grand Teton National Park was first established on February 26, 1929, to protect the peaks, and later grew to take in much of the valley below, thanks in large part to land quietly bought and donated by John D. Rockefeller Jr. Today its 310,000 acres hold a chain of glacial lakes, the upper Snake River and a wildlife assemblage that includes moose, elk, bison, pronghorn, grizzlies and wolves.

Geography

The park stretches north from the town of Jackson to within a few miles of Yellowstone. On its west side rises the Teton Range, crowned by Grand Teton at 13,775 ft, with nine other peaks topping 12,000 ft. To the east spreads Jackson Hole, a mountain valley averaging about 6,800 ft whose lowest point, near the southern boundary, is about 6,350 ft.

A string of lakes rests at the base of the range where Ice Age glaciers poured out of the canyons: Phelps, Taggart, Bradley, Jenny, String and Leigh lakes, and largest of all, Jackson Lake, about 15 miles long. A dam built at its outlet before the park existed raised Jackson Lake by nearly 40 ft. The Snake River leaves the lake and winds south through the valley, braiding among cottonwood islands.

The valley floor is a patchwork of glacial outwash plains, sagebrush flats and moraines. Isolated buttes such as Blacktail Butte and Signal Mountain rise from it, and the historic barns of Mormon Row stand against the mountain skyline on Antelope Flats.

Landmarks

Grand TetonPeak · 13,775 ftThe monarch of the range and the park's highest summit, rising more than 7,000 ft above the valley.
Middle TetonPeakThe southern neighbor of Grand Teton, split by a prominent black diabase dike.
Teton GlacierGlacierA small glacier tucked beneath Grand Teton's northeast face.
Mount MoranPeakA massive peak above Jackson Lake capped by a remnant of Flathead Sandstone and cut by a 150-foot-wide dike.
Jackson LakeLakeThe park's largest lake, a natural glacial basin enlarged by a dam at its outlet.
Jenny LakeLakeA glacier-carved lake at the mouth of Cascade Canyon, surrounded by its moraine.
String LakeLakeA shallow, narrow lake linking Leigh and Jenny lakes, popular with paddlers.
Leigh LakeLakeA quiet lake at the foot of Mount Moran with sandy beaches and backcountry campsites.
Oxbow BendRiverA slow meander of the Snake River where Mount Moran is mirrored and moose, otters and pelicans gather.
Death CanyonCanyonA deep canyon with fine exposures of ancient banded gneiss.
Blacktail ButtePeakA forested butte on the valley floor that survived the glaciers flowing around it.
Mormon RowAreaA line of homestead barns on Antelope Flats where bison and pronghorn graze.

Geology

The Tetons are made of some of the oldest rock in North America. Their gneiss and schist began as sea-floor sand, mud and volcanic ash, then were buried, folded and recrystallized; the oldest dated rock in the park is about 2,680 million years old. Around 2,545 million years ago, magma intruded these rocks and cooled into the granite and pegmatite of the central peaks, and about 765 million years ago dark diabase dikes forced their way through, leaving the black stripes on Mount Moran and Middle Teton.

Through the Paleozoic and Mesozoic eras, shallow seas repeatedly covered the region, laying down thousands of feet of sandstone, shale and limestone. The Laramide orogeny, beginning around 66 million years ago, buckled western North America and raised the ancestral Rockies, but the Tetons as we know them came much later.

Within the last 6 to 9 million years, movement on the Teton Fault began tilting the mountain block up and the Jackson Hole block down. Earthquake by earthquake, the two sides have separated by about 30,000 ft. The Flathead Sandstone that caps Mount Moran lies buried roughly 24,000 ft beneath the valley floor. Much of that motion has happened in the last 2 million years, making the Tetons still young and growing.

Ice ages then sculpted the uplift. Glaciers flowed out of the canyons into Jackson Hole during several glaciations, including the Bull Lake glaciation, which began between 160,000 and 130,000 years ago, and the more recent Pinedale glaciation. They left the moraines that dam today's piedmont lakes and the outwash plains of the valley. The dozen small glaciers now clinging to the high peaks formed during a later cool period within the last 5,000 years.

Deep time

About 2,680 million years agoThe oldest dated rocks in the park formed, later metamorphosed into banded gneiss.
About 2,545 million years agoGranite and pegmatite intruded the gneiss, forming the core of the central peaks.
About 765 million years agoDiabase magma filled cracks to form the dark dikes on Mount Moran and Middle Teton.
542 to 66 million years agoSeas repeatedly flooded the area, depositing thick sedimentary layers.
Beginning about 66 million years agoThe Laramide orogeny raised the ancestral Rocky Mountains.
6 to 9 million years agoThe Teton Fault became active and the modern range began to rise.
160,000 to 130,000 years agoThe Bull Lake glaciation began, carving basins such as Emma Matilda and Two Ocean lakes.
Within the last 5,000 yearsSmall cirque glaciers such as Teton Glacier formed during a cooler episode.

The rocks

Precambrian gneiss and schistAbout 2.7 billion years
Banded metamorphic rock of the range's eastern faces, well exposed in Death Canyon.
Precambrian granite and pegmatiteAbout 2,545 million years
Light granitic rock intruded into the gneiss, forming Grand Teton and the nearby central peaks.
Diabase dikesAbout 765 million years
Black vertical bands on Mount Moran and Middle Teton.
Flathead SandstoneCambrian
A reddish-brown sandstone perched on Mount Moran's summit and buried deep beneath Jackson Hole.
Madison LimestoneMississippian
About 1,000 ft thick, forming cliffs along canyons in the north, west and south of the range.
Chugwater FormationTriassic
Soft, bright red rock deposited on ancient tidal flats.
Pinedale glacial depositsLate Pleistocene
Moraines and outwash that impound Jenny, Taggart and other piedmont lakes.

Trees, Plants & Ecosystems

1,553vascular plant species recorded

Sagebrush flatsJackson Hole valley floor
The park's most widespread habitat, where big sagebrush, bunchgrasses and wildflowers support pronghorn, bison and sage-grouse.
Riparian and wetlandsSnake River and lake margins
Cottonwoods, willows and beaver ponds that draw moose, trumpeter swans and river otters.
Lodgepole pine forestMoraines and lower slopes
Dense stands growing on glacial debris, shaped by fire and bark beetles.
Subalpine forest and meadowUpper canyons below treeline
Subalpine fir, Engelmann spruce and whitebark pine with rich wildflower meadows.
Alpine tundraHigh peaks above treeline
Rock, snowfields and cushion plants home to pikas, marmots and rosy-finches.

Trees

Lodgepole pinePinus contorta var. latifoliaThe most common tree in the park, often dominating moraines.
Whitebark pinePinus albicaulisA keystone species of high elevations whose seeds feed bears and nutcrackers.
Limber pinePinus flexilisA tough, flexible-branched pine of rocky, windswept sites.
Subalpine firAbies lasiocarpaA narrow, spire-shaped fir common near treeline.
Engelmann sprucePicea engelmanniiA cold-loving spruce of canyon bottoms and subalpine forest.
Blue sprucePicea pungensGrows along streams and in moist valley sites.
Douglas firPseudotsuga menziesii var. glaucaFound on warm, dry slopes and buttes.
Quaking aspenPopulus tremuloidesClonal groves turn gold in late September.
Narrowleaf cottonwoodPopulus angustifoliaA willow-leaved cottonwood of the Snake River bottomlands.
Black cottonwoodPopulus balsamifera ssp. trichocarpaA tall floodplain tree along rivers and streams.
Rocky Mountain juniperJuniperus scopulorumA scattered juniper of dry, rocky slopes.

Wildflowers, shrubs & other plants

Mountain big sagebrushArtemisia tridentata var. vaseyanaThe aromatic shrub that silvers the valley floor and shelters sage-grouse.
Arrowleaf balsamrootBalsamorhiza sagittataBig yellow sunflowers that blanket slopes in June.
Scarlet giliaIpomopsis aggregataRed trumpets favored by hummingbirds in dry meadows.
Silky lupineLupinus sericeusPurple-blue spikes among the sagebrush in early summer.
Colorado blue columbineAquilegia coeruleaBlue-and-white spurred flowers in moist, rocky canyons.
Glacier lilyErythronium grandiflorumYellow blooms that follow the melting snow uphill.
CamasCamassia quamashBlue wet-meadow flowers once harvested as food by tribes.
Mule's earsWyethia amplexicaulisGlossy leaves and yellow flowers on open slopes.
Sticky geraniumGeranium viscosissimumPink-purple flowers along forest edges and meadows.
Subalpine larkspurDelphinium barbeyiTall, deep-blue spikes in lush subalpine meadows.
Giant red paintbrushCastilleja miniataCrimson bracts in canyon meadows.
Sky pilotPolemonium viscosumMusky blue clusters on high rocky slopes.
Oneflower helianthellaHelianthella unifloraA tall mountain sunflower of open slopes.

Wildlife

56mammals
180birds
4reptiles
5amphibians
21fish

Mammals

MooseAlces alcesBrowses willows along the Snake River and Gros Ventre River.
ElkCervus elaphusThousands migrate through the park to winter range near Jackson.
American bisonBison bisonA free-roaming herd grazes the valley flats.
PronghornAntilocapra americanaSome make one of the longest land migrations in the lower 48, traveling to and from the Upper Green River basin.
Bighorn sheepOvis canadensisA small, isolated herd lives year-round in the high Tetons.
Grizzly bearUrsus arctosIncreasingly common, especially in the northern part of the park.
Black bearUrsus americanusFrequently seen foraging berries near the lakes.
Gray wolfCanis lupusWolves from the Yellowstone recovery reestablished packs in Jackson Hole.
CoyoteCanis latransHunts voles in the sagebrush flats.
BeaverCastor canadensisShapes wetlands along streams and side channels.
American pikaOchotona princepsA haymaking rabbit relative of talus slopes.
Yellow-bellied marmotMarmota flaviventrisSunbathes on boulders in canyons.
Uinta ground squirrelSpermophilus armatusA common sagebrush squirrel that hibernates much of the year.
River otterLontra canadensisOften seen playing at Oxbow Bend.

Birds

Greater sage-grouseCentrocercus urophasianusMales strut on spring leks in the sagebrush.
Trumpeter swanCygnus buccinatorNorth America's largest waterfowl, nesting on quiet ponds.
Bald eagleHaliaeetus leucocephalusNests in cottonwoods along the Snake River.
OspreyPandion haliaetusFishes the lakes and river all summer.
Sandhill craneGrus canadensisIts rattling calls ring over wet meadows.
American white pelicanPelecanus erythrorhynchosOften floats in groups at Oxbow Bend.
Great gray owlStrix nebulosaA huge owl hunting forest-edge meadows.
Barrow's goldeneyeBucephala islandicaA tree-cavity-nesting duck of mountain lakes.
Harlequin duckHistrionicus histrionicusBreeds on fast, clear mountain streams.
American dipperCinclus mexicanusBobs and dives in rushing creeks.
Mountain bluebirdSialia currucoidesA sky-blue bird of open sagebrush and meadows.
Clark's nutcrackerNucifraga columbianaHarvests and caches whitebark pine seeds.
Calliope hummingbirdStellula calliopeThe smallest breeding bird in the United States.
Black-billed magpiePica hudsoniaA long-tailed, iridescent bird of valley thickets.

Reptiles & amphibians

Western toadAnaxyrus boreasA declining toad of ponds and wetlands.
Boreal chorus frogPseudacris maculataIts creaking calls fill snowmelt ponds.
Western tiger salamanderAmbystoma mavortiumThe park's only salamander, found in fishless ponds.
Wandering garter snakeThamnophis elegans vagransThe most common snake in the park.
Valley garter snakeThamnophis sirtalis fitchiA colorful garter snake of wet meadows.
Rubber boaCharina bottaeA small, secretive constrictor of rocky forest openings.

Fish

Cutthroat trout (Snake River fine-spotted)Oncorhynchus clarkiiThe native trout of the Snake River, known here for its fine-spotted form.
Lake troutSalvelinus namaycushA non-native char stocked in Jackson Lake.
Brook troutSalvelinus fontinalisA non-native trout in some streams and small lakes.

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

Climate & When to Visit

Grand Teton has long, cold winters and short, bright summers, and snow and frost are possible in every month. Jackson Hole sits at nearly 7,000 ft, so even July nights can dip near freezing, while cold air pools on the valley floor on clear winter nights and drives temperatures far below zero.

The Teton Range wrings moisture from Pacific storms, so the peaks receive far more snow than the sagebrush flats below. Summer brings warm days and frequent afternoon thunderstorms that build over the peaks. Autumn alternates sunny days, cold nights and early storms, while spring is a slow, muddy thaw of rain and snow.

Spring
April through June alternates mild days and cool nights with rain and snow. Lower trails melt out by June while high canyons stay snowbound.
Summer
July and August bring warm days, cool nights and common afternoon thundershowers. This is the prime season for climbing and high-country hiking.
Autumn
September through November brings sunny days, cold nights, golden aspens and the elk rut. Rain and occasional snowstorms become more frequent.
Winter
From December to April snow blankets the valley and mountains. Days between storms are sunny, but nights are frigid and many roads close.

Weather hazards

Lightning: Summer storms build quickly over the peaks, so start climbs early and descend exposed ridges by early afternoon.
Snow in any month: Pack warm layers and rain gear even in July, because summer snow and hail are possible.
Avalanches: Winter and spring backcountry travel requires avalanche training, beacons and a current forecast.
Extreme winter cold: Cold air settles in Jackson Hole on clear nights, so plan for well below zero temperatures.
Cold, swift water: Snowmelt-fed streams and the Snake River are dangerously cold and powerful in early summer.

Grand Teton Questions

When is the best time to visit Grand Teton National Park?

Late June through September is the most popular window, with open trails, wildflowers and warm days. September offers fall color and active wildlife with fewer crowds, while winter brings quiet, snowy landscapes.

What is the weather like in summer?

Summer days are usually warm and sunny with cool nights, but afternoon thunderstorms are common. Because the valley sits near 7,000 ft, pack a warm layer, and remember that snow is possible even in summer.

Why do the Tetons have no foothills?

The range is a tilted block along the Teton Fault. As the mountains rose, the valley floor dropped, so the peaks rise directly from Jackson Hole without gradual foothills.

How old are the Teton Mountains?

The rocks are ancient, with the oldest dated at about 2.68 billion years. The mountains themselves are young: the Teton Fault began lifting the modern range within the last 6 to 9 million years.

Where is the best wildlife viewing?

Oxbow Bend is excellent for moose, otters and waterbirds, and Antelope Flats and Mormon Row are good for bison and pronghorn. Early morning and evening offer the best chances.

Are there glaciers in Grand Teton?

Yes. About a dozen small glaciers survive near the highest peaks, including Teton Glacier below Grand Teton and several on Mount Moran. They formed within the last 5,000 years and are shrinking.

More parks in the Rocky Mountains

← Grand Canyon National Park Great Basin National Park →

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