Marine Corps Reference Publication MCRP 12-10A.2 (Formerly MCRP 3-35.1B) Mountain Leader's Guide to Winter Operations 2 May 2016, is a reference for trained winter mountain leaders to use during operations in snow. This publication is to be used with the Marine Corps' mountain warfare and cold weather series doctrinal publications. It contains winter operations tactics, techniques, and procedures covering combat ski instruction and skills, crawls, firing positions, avalanche hazard assessment and mitigation, and crossing frozen waterways. It also covers, snow tracking and deception, skiborne patrolling considerations, and over-the-snow vehicle employment. Focusing on a standard method of instruction, this publication stresses only the cold weather skills necessary for Marines to go into combat. Because of the rapid turnover in personnel, the many units that train annually, the multitude of training commitments, and the short winter season, the Marine Corps Mountain Warfare Training Center cannot train all scout skiers or units. Therefore, in combat, Marines may receive ski instruction from their unit's qualified winter mountain leaders. This publication supersedes MCRP 3-35.1B, Instructor's Guide to Combat Skiing, dated November 1991.