Guide and Outfitter working out of Banff and Lake Louise, Tom Wilson, established Powderhorn Ranch at Kootenay Plains in 1900 near the confluence of Whiterabbit Creek and Northern Saskatchewan River. In that year they rented a cabin owned by Silas Abraham of the Bighorn First Nation and in 1902 and added a store. His store made the Stoney’s become dependant as Wilson provided them with rifles, ammunition, tobacco and alcohol. Wilson remained at Kootenay Plains for 8 years. The site is now flooded by the hydroelectric reservoir. Before flooding in 1972 both Silas Abraham cabin and Wilson’s store were moved by the Alberta Government to Two O’Clock Creek area. Wilson's store burned down in spring 1992. Silas Abraham cabin is still standing on Stoney’s land in Two O'Clock area.

Two O'clock Creek in summer normally is dry in the morning but in the early afternoon is full of floods. The creek is fed by underground streams from Wilson Glacier, and the heat of the day with the sun shining melted snow on the glacier to feed the underground streams. Historically, the creek’s surrounding area continues to play one of the most important roles in the history of Kootenay Plains. On June 1, 1807, David Thompson, his wife Charlotte Small and children travelled through this area and stayed for one night at this location. In his journals, Thompson described the abundance of game in the Kootenay Plains and recorded several encounters with bison. On June 20, 1810, he reported shooting a bull at Kootenay Plains.

In 1911the Ex Coelis-group was named “Kadoona” by Mary Schaffer. This was her pronunciation of the Stony name, “Kedonnaha Tinda”, or “Meadow of the Winds” – now known as the Kootenay Plains. Ex Coelis is Latin for “Out of the Clouds” and is the motto of the First Canadian Parachute Battalion, one of eight battalions which made up the Sixth British Airborne Division during World War II. In 1997 the individual peaks were named for WWII battles (Normandy, Ardennes and Rhine) that the battalion was involved in. “Elbe” is a river in Germany where the battalion met up with the Russian army towards the end of the war. Stan Waters is the highest peak in the complex. It is named for one of the battalion members who went on to be a successful Calgary businessman and eventually served on the Canadian senate in Ottawa.