Lt. Henry James Warre of the 14th Regiment and Mervin Vavasour of the Royal Engineers were ordered by the Governor General to cross the Rockies disguised as private adventures and evaluate the mountain passes from a military point of view.
Warre documented their journey in a journal that was later published as, "Sketches in North America and the Oregon Territory." He described the trip as follows, "Our passage over the magnificent range of the lofty mountains was not accomplished without much difficulty, and a fearful sacrifice of the noble animals that aided us in the transport. We left Edmonton with sixty horses; on our arrival at Fort Colville, on the Columbia River, we had only twenty-seven, and several of these so exhausted they could not have continued many more days. The steepness of the mountain passes, the want of proper nourishment, the fearful falls that some of the animals sustained, rolling in some instances many hundred feet into the foaming torrent beneath, combined to cause this great loss. The scenery was grand in the extreme; similar in form to the Alps of Switzerland, you felt that you were in the midst of desolation: no habitations, save those of the wild Indians were within hundreds of miles; but few civilized beings had ever even viewed this.