One man died and another sustained critical injuries in a head-on collision Tuesday afternoon on Highway 26 at milepost 74 in Wasco County.  The Oregon State Police says a preliminary investigation revealed a pickup truck operated by 65-year-old Lanny Hawley of Gresham was traveling eastbound on Highway 26 at about 5:30 p.m. on Tuesday when for unknown reasons the truck crossed over the center line into westbound traffic and struck an SUV driven by 52-year-old Kyle Estes of Medford.  Estes was pronounced deceased at the scene due to injuries sustained in the crash.  Hawley was air lifted to a trauma hospital in Bend for critical injuries.  Highway 26 was closed for approximately six hours following the crash.