An island ecosystem that escaped glaciation, rising above the ice sheets. Plants and animals found nowhere else on the prairies survive here, including fourteen endemic species. A biological time capsule from before the ice ages.
Erik Lizee / Eriklizee at English Wikipedia, Public domain, via Wikimedia Commons
An island in a sea of ice
During the last ice age, the Wisconsinan Glaciation, most of Canada was covered by the massive Laurentide and Cordilleran ice sheets. The Cypress Hills, however, was an unglaciated island, or "nunatak," projecting above the ice. Reaching a maximum elevation of 1,468 meters (4,816 feet), the hills form the highest point of land in Canada between the Rocky Mountains and Labrador. This elevation was just enough to prevent the ice sheets from overrunning the plateau.
The hills are an erosional remnant of a much larger plain, capped by the resistant Cypress Hills Formation—a layer of conglomerate and sandstone up to 100 meters thick that was laid down by rivers flowing from the Rockies during the Eocene to Miocene epochs. This tough caprock protected the underlying softer shales and sandstones from being scraped away by the glaciers that scoured the surrounding plains. As the ice sheets melted, their meltwater carved large channels and coulees around the newly exposed upland. The geology of the hills also contains a collection of vertebrate fossils from the Tertiary period.
A biological time capsule
The unglaciated refuge of the Cypress Hills created a unique biological situation. The area is a humid, forested island in the semi-arid prairies, supporting plants and animals that are disconnected from their main populations in the Rocky Mountains, over 200 kilometers to the west. The hills support the only naturally occurring lodgepole pine (Pinus contorta) forest on the Canadian prairies. White spruce (Picea glauca) forests grow on cool, moist, north-facing slopes.
This isolation has preserved a distinct collection of species. The area hosts at least 18 species of orchids, more than anywhere else on the prairies. Some species found here, like the Spring Coralroot orchid (Corallorhiza wisteriana) and Cooper's Rocky Mountain snail (Oreohelix strigosa cooperi), are found nowhere else in Canada. These disjunct populations are living relics from a time before the ice sheets separated them from their mountain counterparts. The hills host over 220 species of birds and 47 species of mammals. Some mammals, like elk and red squirrels, were reintroduced in the 20th century after being eliminated in the late 1800s.
💡Fun Facts
The name "Cypress Hills" is a misnomer. French-Canadian Métis hunters called the local lodgepole pine "cyprès," and the name stuck.
The 1873 Cypress Hills Massacre, an attack on an Assiniboine camp by American wolf-hunters, prompted the creation of the North-West Mounted Police (forerunners to the "Mounties").
Fort Walsh was established nearby in 1875 to bring order to the region and is now a National Historic Site.
Archaeological evidence shows human habitation in the hills dating back at least 7,000 to 8,500 years.
Cypress Hills Interprovincial Park is open year-round, though visitor services and facility hours vary by season.
Admission
A valid park entry permit is required for all vehicles.
Accessibility
The main visitor areas and some viewpoints are accessible by paved roads. Trails consist of natural terrain with varying difficulty. The visitor centre is wheelchair-accessible.
