CALGARY Access to Mount Yamnuska an area popular for climbing and hiking west of Calgary will be closed from the end of May until November as crews work to upgrade some sections of trail, build new ones and decommission others. Found in the Bow Valley Wildland Provincial Park just north of Highway 1 near the Highway 40 exit, Mount Yamnuska features a recognizable, 360-meter cliff face. Members of the Stoney Nakoda First Nation call it Îyâ Mnathka, or E-Yamnuska, which means flat-faced mountain. Main East Trail Upgrading to Raven s End, decommissioning all other unsanctioned routes; Main West Trail Upgrading to the bottom of the scree slope;