text: Appendix D
   Mortars are ideal for targets on reverse slopes and over intermediate crests because of their
  high-angle fires.
   Airbursts on reverse slopes are extremely effective.
  TARGET ACQUISITION AND OBSERVATION
  D-66. The following are considerations when FOs are involved in mountain operations:
  * The observers should be positioned on high ground and spread out to overcome terrain masks and
  compartments.
  * The observers may need mountaineering equipment to get to the best positions, or they may be
  airlifted.
  * Terrain sketches and visibility diagrams are useful to deliver fast, accurate fires and to identify
  blind spots.
  * Heavy fogs or low clouds may obscure observation.
  * Observers (without laser rangefinders) who are looking up tend to underestimate range, whereas
  observers looking down tend to overestimate range.
  D-67. Air observers:
  * Are very effective to observe beyond terrain masks, in deep defilade, and on reverse slopes.
  * Complement the FIST observers.
  * Can be used to detect deep targets.
  * May be confined to valleys and lower elevations because thin air at high elevations makes flying
  difficult.
  D-68. Radar considerations in mountain operations include:
  * Radars should concentrate on terrain that can be occupied by artillery and mortars (as determined
  by IPOE).
  * Terrain masks can degrade the effective range of the radar.
  * Additional use of ground surveillance radars and remote sensors may be required.
  * More extensive use of shelling reports may be required.
  TARGETING
  D-69. The intelligence officer's IPOE should identify the following:
  * Routes that can be used by the enemy to attack, withdraw, and resupply.
  * Likely position areas for enemy indirect fire assets, C2, support assets, and observation posts.
  * Terrain that is subject to snows slides, rockslides, or avalanches. These may deny the enemy use
  of roads and trails and may destroy elements in defilade.
  POSITIONING
  D-70. Usually, position areas for mortars and artillery are limited and access thereto may be restricted.
  Because of the need to fire high angle, it is important that the mortars and artillery be positioned in defilade
  to increase their survivability. Positioning considerations include:
  * Helicopters should be used to airlift artillery into position areas. These air assets also may be
  required to provide ammunition resupply.
  * Helicopters may be useful in performing survey by use of Doppler radar.
  * Positioning along dry riverbeds is hazardous because of the danger of flash flooding.
  * Towns and cities usually have flat areas (school yards, parks, stadiums, and so forth) that can
  accommodate firing batteries. However, these towns and cities are often enemy objectives and
  may be targeted.
  * Most mountainous flat land is farmland and is difficult for towed artillery to negotiate from spring
  to fall. However, in winter, if the ground is frozen, farmland provides good firing positions for
  mortars and artillery.