(Clark Co., WA)  --  Clark County sheriff's deputies are investigating an all-terrain-vehicle accident that left a rider seriously injured.  Authorities say the crash happened last night as two ATVs were being ridden together at the intersection of Northeast Berry Road and Northeast 240th Avenue.  Deputies say the driver of one of the ATVs failed to complete a turn and left the roadway, then struck a power utility box.  The passenger who was injured was airlifted to a hospital.