OverviewDiadem Peak sits at the north end of the head of the Woolley Creek drainage just north of the Columbia Icefield. It shares this area with neighboring peaks Mount Woolley and Mount Cromwell. Two Main routes to the summit of Diadem Peak are accessed from this side of the mountain, the South Ridge (II) and the South East Face (II) each of which are moderate climbs. Another route, accessed from the north side of the mountain and much more difficult, is the North Face, Humble Horse (IV, 5.7 WI4).
Getting ThereTake Alberta, Canada's Icefields Parkway toward the Icefields Center. Park your vehicle at an unmarked but very large pullout adjacent to the Woolley Creek drainage and about 12 km north of the Icefields Center. Wade across the wide and braided Sunwapta River (one may consider using a pair of sneakers which may be left on the opposite bank and used for the return) and find a good but steep trail heading into the woods on the south side of Woolley Creek. Climb this shoulder to bypass a large, cascading waterfall; it eventually gains and follows an intermittent path at creek-level. Follow cairns west into talus and moraine eventually turning toward the north until several good, walled bivy sites are reached. About 3 or 4 hours hiking time.
I have not done the approach to the north side of the mountain and, futhermore, have no second hand knowledge of it other than that which is available in Sean Daugherty's Selected Alpine Climbs book. He says that parking is available at an interpretive pull-out 19km north of the Icefields Visitors Center. Ford the Sunwapta River and follow Diadem Creek along a morainal crest on the right. Surmount the valley's headwall by hiking around its north side, then contour above the headwall onto the glacier below Diadem's north face. Good luck.