Salmon River, Idaho

William Clark drew this “white salmon” in his journal in 1806. The effects of climate change have degraded the habitat of the Salmon River, where the expedition once caught 500 similar fish in one day.

Oregon Historical Society

Downstream from here, on August 22, 1805, Clark and a small party explored ahead along the Salmon River. They came upon some Shoshone families drying fish and berries. Clark’s party tried spearing fish in the river but only caught one small salmon. Back at the main camp, Lewis’s group had better luck, using a brush drag to pull more than 500 fish from the river.26

Climate change and extreme weather events have altered Salmon River conditions. In July 2015, a record heatwave and low snowpack created water temperatures that killed most of the naturally migrating adult sockeye salmon in the river. Average water temperatures are expected to further rise, reducing the river flow by up to half and threatening the endangered salmon population.27

Citations:
26 NPS, “Salmon River,” Lewis & Clark National Historic Trail, January 12, 2021, https://www.nps.gov/articles/000/salmon-river.htm; Meriwether Lewis, August 22, 1805 entry, in Gary E. Moulton, Journals of the Lewis and Clark Expedition, https://lewisandclarkjournals.unl.edu/item/lc.jrn.1805-08-22#n21082210.
27 U.S. Global Change Research Program, “Chapter 27: Northwest,” in Fifth National Climate Assessment, edited by A. R. Crimmins, et al. (Washington, DC: U.S. Global Change Research Program, 2023), https://nca2023.globalchange.gov/chapter/27/ (see Box 27.1 Snake River Sockeye Salmon).

Climate Change:Lewis and Clark Trail

Lewis and Clark NHT Visitor Centers and Museums

This map shows a range of features associated with the Lewis and Clark National Historic Trail, which commemorates the 1803-1806 Lewis and Clark Expedition. The trail spans a large portion of the North American continent, from the Ohio River in Pittsburgh, Pennsylvania, to the mouth of the Columbia River in Oregon. The trail is comprised of the historic route of the Lewis and Clark Expedition, an auto tour route, high potential historic sites (shown in black), visitor centers (shown in orange), and pivotal places (shown in green). These features can be selected on the map to reveal additional information. Also shown is a base map displaying state boundaries, cities, rivers, and highways. The map conveys how a significant area of the North American continent was traversed by the Lewis and Clark Expedition and indicates the many places where visitors can learn about their journey and experience the landscape through which they traveled.