(Portland, OR) -- A Lake Oswego mother and her 12-year-old daughter are dead following a crash on Christmas Day. Police say Deirdre Lynne Mackey and her daughter were driving on Highway 26 in Wasco County Monday when their car slid into oncoming traffic and struck another vehicle head-on. Mackey and her daughter were pronounced dead at the scene. The driver of the other vehicle and his passenger both suffered non-life-threatening injuries.