Portage Glacier

Portage Glacier is the most visited natural attraction in Alaska — a dramatic river of blue ice from the Sargent Icefield that calves into the cold, iceberg-filled waters of Portage Lake in a spectacular valley just 50 miles southeast of Anchorage, framed by the steep walls of the Chugach Mountains. It is accessible by a paved road from the Seward Highway, making it one of the few glaciers in Alaska reachable without a flight or ferry.

The Begich, Boggs Visitor Center on the lake’s shore offers exhibits and the summer boat tour, which cruises to the glacier’s face among the floating icebergs — the only way to get close to the glacier, as it has retreated far enough that it is no longer visible from the visitor center. A 1960s photograph shows the glacier extending to near the visitor center’s current location — one of the most striking visual records of glacial retreat in North America. Accessible, beautiful, and thought-provoking, Portage Glacier is a treasured natural icon of Alaska.

Portage Glacier’s primary experiences are the summer boat tour (cruising across Portage Lake among icebergs to reach the glacier’s calving face — the only way to see the glacier up close, as it has retreated behind the headwall; the tour runs from June through September, operated by a concessionaire), the Begich, Boggs Visitor Center (excellent exhibits on glaciology, the retreat of Portage Glacier, and the ecology of the Chugach), hiking the valley trails (the Byron Glacier Trail leads to the base of Byron Glacier — one of the few glaciers in Alaska that can be hiked on without a guide, with glacial ice at the trail’s end; the Portage Lake Trail offers lake views), and photography of the icebergs and mountain scenery. The boat tour and the Byron Glacier hike are the signature draws.

Summer (late May through September) is the season, when the visitor center and boat tours operate and the valley’s trails are snow-free. June brings the snow-free valley and early-season icebergs; July and August are warmest and busiest; September is quieter and brings early-fall color on the tundra slopes. The boat tour typically operates June through September (check current schedule). Winter brings deep snow to the valley and transforms it into a snowshoe and ski-touring destination. Summer for the boat tour and the Byron Glacier hike are the highlights — arrive early to avoid crowds (the proximity to Anchorage makes this a popular day trip).

The Portage Valley and the Portage Pass were critical travel routes for the Alutiiq/Sugpiaq people crossing from Prince William Sound to Cook Inlet; the pass was a trade and travel corridor for millennia. During the Alaska gold rush era, Portage Pass was used as a route to the Klondike. The 1964 Good Friday Earthquake (9.2 magnitude — the largest in North American recorded history) sank the Portage area by up to 10 feet, inundating the forested lowland with saltwater and killing the trees (the gray tree trunks still visible as “ghost forests” in the flats above the valley are a haunting legacy of the earthquake). Portage Glacier itself has retreated dramatically — in the 1970s it was visible from the highway; today it has retreated behind the lake and requires a boat to see. The Begich, Boggs Visitor Center (named for two U.S. Congressmen who disappeared in a plane crash nearby in 1972) opened in 1986.

Portage Glacier flows from the Sargent Icefield (part of the Chugach Mountains’ network of valley glaciers) into Portage Lake — a glacially carved, moraine-dammed lake whose silty, pale-blue water is laden with glacial flour. The glacier has retreated approximately 3 miles since the early 20th century, exposing the lake as it pulled back. The valley itself is a classic U-shaped glacial valley carved by the Portage Glacier during the Pleistocene. The 1964 earthquake’s subsidence of the Portage Flats created the saltwater “ghost forest” — the dead Sitka spruce trunks standing in the now-inundated former forest floor. The glacial valley, the retreating glacier, the moraine-dammed lake and the earthquake subsidence define Portage’s geology.

The Portage Valley’s forest, wetlands and lake support varied wildlife — brown and black bears (brown bears are frequently seen in the valley, particularly near the salmon streams at the valley floor), moose (common in the wetlands and willows), Dall sheep (visible on the steep mountain walls above the valley), marmots, beavers, and a rich birdlife (bald eagles, mew gulls, Arctic terns, and various waterfowl on the lake). Salmon run up the streams flowing into Portage Lake in late summer, attracting bears and eagles. The combination of mountain, valley, lake and wetland habitats in a relatively small area supports notable wildlife diversity close to Anchorage.

Portage Valley showcases ecological succession following glacial retreat — as the glacier has pulled back over the past century, the newly exposed terrain is being colonized in a progression from bare gravel to willows, alder and eventually cottonwood and Sitka spruce forest (the process visible in the different vegetation ages up the valley). The saltwater ghost forest in the Portage Flats (created by the 1964 earthquake) is another ecological transition — as the dead forest slowly falls and is replaced by salt-tolerant species. The valley’s salmon streams and the lake’s cold, turbid water form the base of the local food web. Protecting the retreating glacier, the salmon streams and the recovering landscape sustains both the ecology and the beauty of Portage Valley.

Portage Glacier holds a treasured place among the natural icons of southcentral Alaska — Alaska’s most visited natural attraction, a dramatic glacier and iceberg lake just an hour from Anchorage, one of the most striking visual records of glacial retreat in North America (the old photographs showing ice where the visitor center now stands are among the most powerful climate-change images in any national park), and a landscape shaped by the 1964 earthquake’s dramatic subsidence. Its combination of accessibility, grandeur and scientific significance makes it exceptional. Portage Glacier is a cherished natural icon of Alaska.

Portage Glacier is in Chugach National Forest, about 50 miles southeast of Anchorage via the Seward Highway (one of Alaska’s most scenic drives, along Turnagain Arm) to the Portage Valley Road, then 5 miles to the Begich, Boggs Visitor Center. The road is paved and accessible by passenger car. Anchorage has full services; the Alaska Railroad also stops at the Portage Glacier Road junction. A fee applies for the boat tour (check with the concessionaire for the current schedule and pricing); the visitor center and trails are free. Check the Chugach National Forest for visitor center hours, boat tour schedule and current conditions before visiting.

The U.S. Forest Service (Chugach National Forest) manages Portage Glacier and the valley. Visitors help by staying on designated trails (the recovering vegetation on the glacier forelands is fragile), keeping safe distances from bears and wildlife (this is active brown bear habitat), packing out all trash, and following all forest rules. The boat tour provides essential access to the retreating glacier without requiring foot traffic on the unstable glacial foreland. The retreating glacier, the recovering ecological succession on the deglaciated terrain, and the salmon streams are the most sensitive conservation features. Protecting the valley’s wildlife and recovering landscapes sustains the ecology of Portage.

Brown bears are present and frequently seen in the Portage Valley — carry bear spray, make noise on trails, keep your distance from all bears, and be especially cautious near salmon streams in late summer. The lake’s icebergs occasionally calve unexpectedly (stay back from the water’s edge near icebergs); the boat tour keeps safe distances from the glacier face. The Seward Highway along Turnagain Arm (the drive to Portage) is one of Alaska’s most avalanche-prone highways in winter and spring; check conditions before driving in those seasons. Respect the bears, the icebergs and the highway conditions.

Visitor center and hiking trails are free (open year-round, but visitor center hours are seasonal — check Chugach NF). Boat tour fee required (check current operator for schedule and pricing). Stay on designated trails; respect closures protecting salmon streams and bear activity areas. No collecting of any natural or cultural materials. Bear-safe food storage required. Pack out all trash. Check the Chugach National Forest for current visitor center hours, trail conditions and any wildlife-related closures before visiting.

The town of Whittier (accessible through the Anton Anderson Memorial Tunnel, the longest combined rail-vehicle tunnel in North America — a fascinating engineering feature, 2.5 miles long, shared by trains and cars alternately; the Whittier gateway to Prince William Sound’s kayaking, glacier cruises and wildlife), Prince William Sound (the spectacular fjord and island sea accessible from Whittier), the Seward Highway (one of Alaska’s great scenic drives, along Turnagain Arm with beluga whale sightings common in summer), and the city of Anchorage (50 miles north) define the region. Portage Glacier anchors a popular and rewarding Anchorage day-trip circuit: Portage Glacier – Whittier tunnel – Prince William Sound.

Take the boat tour to actually see the glacier (it has retreated entirely behind the headwall and is invisible from the visitor center or shoreline — the boat is the only way to experience the ice directly). At the visitor center, compare the old photographs of the glacier extending to the visitor center’s location (the most striking visual record of glacial retreat in Alaska) with the current view of the empty lake. After the boat tour, hike the Byron Glacier Trail (2.5 miles round trip) to walk on glacial ice at the trail’s end — Byron Glacier is one of the few Alaska glaciers accessible on foot without a guide. Then drive through the Anton Anderson Tunnel to Whittier for a Prince William Sound glacier cruise or kayak trip.