A 25 acre wildfire was discovered late Sunday afternoon on the Clackamas River Ranger District of the Mt. Hood National forest.  The Collawash Fire is burning in grass and brush under a Bonneville Power Administration powerline corridor along Forest Road 63 south of Raab Campground.  A Forest Service spokesperson says multiple engines, water tenders, and hand crews are responding to the incident and making good progress in building a line around the fire. The cause of the wildfire is under investigation.   No closures are currently in place but visitors should use caution driving near the fire area due the presence of firefighters and equipment along roads in the vicinity and the possibility of reduced visibility caused by smoke.