Waves caused by strong winds have eroded the shoreline of Okanagan Lake and destroyed a section of the concrete retaining wall along Highway 97 in Peachland, British Columbia.An evacuation order was issued for 11 houses where the water has risen high enough to wash out Mill Road, which borders the lake in Naramata. Erosion of the shoreline has been a concern since May when boating advisories were put in place to keep wakes from causing more damage.