Baird Glacier originates in the Stikine Icefield in the Boundary Ranges near the Alaska–British Columbia border and flows southwest for 24 miles (39 km) to an outwash plain 2 miles (3.2 km) north of Thomas Bay’s head, about 100 miles (162 km) southeast of Juneau and 22 miles (35 km) north-northeast of Petersburg, Alaska. Thomas Bay extends 10 miles (16 km) northeast from Frederick Sound into the Coast Mountains. It was named for Lieutenant Commander Charles M. Thomas, captain of the US Coast and Geodetic Survey vessel Carlile P. Patterson (1887–89). That same year, Thomas christened the glacier for Spencer F. Baird, a pioneering naturalist noted for his studies of North American birds and his service as Secretary of the Smithsonian Institution (1850–87) and US Commissioner of Fish and Fisheries (1871–87). The Coast Mountains divide into the Pacific, Kitimat, and Boundary Ranges—the latter the largest and most northerly. The Boundary Ranges comprise granitic intrusions known as the Coast Mountains Batholith or Coast Plutonic Complex, remnants of a Late Cretaceous volcanic arc called the Coast Range Arc. This batholith now separates the Stikine terrane to the east from the Alexander terrane to the west. Both the Stikine Icefield and Baird Glacier overlie the Coast Plutonic Complex, characterized by a sill of tonalite and quartz diorite that intruded during the Late Cretaceous and Paleocene. Much of Southeast Alaska’s Alexander Archipelago rests on Paleozoic and Early Mesozoic rocks of the Alexander terrane, which collided with the Stikine terrane during the mid-Cretaceous, about 100 million years ago. The metamorphic rocks beneath Thomas Bay, linked to the evolution of the Coast Plutonic Complex, are known as the Ruth Assemblage. A notable formation at the glacier’s head is Devils Thumb—Taalkhunaxhkʼu Shaa in Tlingit—a peak whose thumblike shape and name, meaning ‘the mountain that never flooded,’ recall its legendary role as a refuge during the Great Flood.

Indigenous peoples have occupied present-day Southeast Alaska for roughly 10,000 years. Tlingit oral history recounts a migration from the Stikine homeland when fjords and straits were ice-filled; along the coast, they encountered an earlier people who were either defeated or assimilated. Shortly after World War II, geologists surveying west‑central British Columbia reported numerous alpine cairns along the lower Stikine River. Cairn sites appeared on both banks but were most prominent at Geology Ridge and Pereleshin Mountain, where over 20 cairns were recorded. A recent study suggests these structures—built around 500 AD—served as boundary markers between cultural groups. The US Forest Service has documented archaeological evidence that Thomas Bay was a traditional hunting and trapping area for the Stikine Tlingit of the Taalkweidí clan, who maintained a year‑round village at the bay’s mouth and at least one additional camp before European contact. The first Europeans likely explored the area on Russian and British vessels engaged in the maritime fur trade in the late 1700s. In 1793, James Johnstone, an officer under Captain George Vancouver, surveyed Frederick Sound but omitted Thomas Bay from subsequent charts. Following the 1867 Alaska Purchase, miners and fishers arrived to exploit the new territory. In 1921, a gold lode was discovered at Elephant Head on Thomas Bay’s north arm and developed by Colp & Lee of Petersburg; another vein was found in the southeast arm, south of Spray Island. In 1915, Thomas Bay hosted the first documented beam trawl shrimp fishery in Southeast Alaska. Floating canneries processed the catch, and by 1921, five processors were operating. The fishery’s fleet size, production capacity, and fishing grounds expanded well into the 1950s, making it the region’s major shrimp fishery until 1959.

Baird Glacier drains the west side of the Stikine Icefield, descending from over 6,000 feet (1,829 m) to a proglacial lake at about 33 feet (10 m). Icebergs calved from the glacier’s front float in the lake, which drains via a stream flowing roughly 2 miles (3.2 km) through an extensive outwash plain that connects to Thomas Bay’s head. Several tributaries join Baird Glacier. The Witches Cauldron—a glacier‐filled basin from the south—merges at about 8.5 miles (14 km); the Oasis Glacier joins from the north at roughly 16 miles (26 km); and the North Baird Glacier meets it at around 22 miles (35 km). Baird Glacier’s terminal moraine is a long mound of cobbles, boulders, and sand left behind when its terminus remained grounded for many years. Decades of sand and gravel deposition, coupled with postglacial rebound, formed the outwash plain, which experiences periodic flooding from outburst floods draining supraglacial lakes at higher elevations. Between 1948 and 2000, Baird Glacier down-wasted substantially and now impounds large volumes of water in the Witches Cauldron, where a tributary experienced a 6-mile (9.5 km) ice flow reversal. Satellite imagery of stranded icebergs suggests that glacial outburst floods, or jökulhlaups, have occurred from a lake at the tributary’s head. If down-wasting continues, glacier-dammed lakes in the Witches Cauldron and elsewhere will expand, increasing flood frequency and destabilizing the glacier’s terminus at the outwash plain. Abandonment of the plain could trigger catastrophic retreat, as Baird Glacier is probably grounded well below sea level. Its retreat now joins that of other Stikine Icefield glaciers, such as Sawyer, Patterson, and Great Glacier. Read more here and here. Explore more of Baird Glacier and Thomas Bay here: