The Hungry Horse News reports that fire investigators have determined the 17,000-plus acre Thompson Fire in Glacier National Park was caused by lightning. Meanwhile, Glacier Park has eased trail restrictions east of the blaze. The Upper Two Medicine Lake, Dawson-Pitamakan, Cut Bank Creek and Triple Divide Pass Trails have all reopened. The Cut Bank Pass trail, however, remains closed as it drops down into the fire area. Read the full story here.