S - On top of an awning on the left hand side before heading through the mucus doors.

T - Next to a truck and some ammo when you come to the point of meeting the Snow Pirates.

O - On a small ledge just past the tower, this is just before the building that you have to anchor your way up several stories.

R - On top of a garbage dumpster type of thing on the left hand side while inside the old train station area.

M - Just above the staircase that goes down inside the building that is on the right hand side before heading to large walled off area ahead.