Encyclopedia of the Great Plains

PALLISER'S TRIANGLE

James Hector, a member of the British expedition of 1857–60 to the western interior of Canada, led by Capt. James Palliser, described the "arid district" of the Canadian Prairies as "a triangular region," with its apex reaching 52 north latitude and its base extending from 100 west to 114 west along the U.S. border (49 north latitude). This is the genesis of the term "Palliser's Triangle," which is still widely used. The cities of Lethbridge and Medicine Hat, Alberta, and Swift Current, Saskatchewan, are located within Palliser's Triangle, which is better described as experiencing subhumid or semiarid rather than truly arid conditions. Annual precipitation averages ten to fourteen inches, to which winter snowfall contributes two to three inches of water equivalent. This results in a climatic designation of steppe rather than desert or semidesert. Within the triangle, as Hector himself reported, there are localities with more humid environments. These include the Cypress Hills, straddling the Alberta-Saskatchewan border, receiving fifteen to nineteen inches annual precipitation and supporting a forest cover, especially on north-facing slopes. In most of the region, which occupies about 73,000 square miles, shortgrass prairie is the natural vegetation.

The southeast corner of the triangle defined by Hector lies in today's southwestern Manitoba, but the true dry belt of the Canadian Prairies extends only about as far east as 104 west on the forty-ninth parallel. Ranching, dryland wheat cultivation, and oil and gas extraction are the main industries, with some specialized irrigation agriculture around Lethbridge. Near Val Marie in southern Saskatchewan, about 300 square miles have been included in the Grasslands National Park Reserve.

Alexander H. Paul University of Regina

Hector, James. "On the Capabilities for Settlement of the Central Part of British North America." Edinburgh New Philosophical Journal, New Series 14 (1861): 263–68.

Spry, Irene M. The Palliser Expedition: An Account of John Palliser's British North American Expedition, 1857–1860. Toronto: Macmillan of Canada, 1963.

Warkentin, John. The Western Interior of Canada: A Record of Geographical Discovery. Toronto: McClelland and Stewart, 1964.