MCRP 12-10B.1, page 329

d. The many reflective surfaces found in built-up areas may cause false images, particularly for laser range finders and laser target designators. e. Thermal imaging devices may not be able to see through large amounts of dust particles suspended in the air. f. Smoke and dust degrade the effectiveness of night vision devices. g. Fog degrades long-range target acquisition from thermal sights. h. Weapons flashes within enclosed areas appear to be much brighter. This causes Marines to lose their night vision and washes out light intensification devices. 5. Considerations. The environment of built-up areas presents special challenges and considerations during periods of limited visibility. a. The use of glint tape, thermal tape, or chemiluminescent lights is an important consideration. These can be used to mark the FLOT, casualties, cleared buildings and rooms, weapons positions, and individual Marines. Their use must be clearly addressed in the unit’s SOP. When markers are used for extended periods, their meanings should change because the enemy may be able to capture or manufacture and use these marking devices to their advantage. b. The use of tracer and incendiary ammunition may be restricted to prevent fires. The light of fires whites out some night vision devices and may interfere with or confuse thermal devices. c. The control of power stations may be essential to operations during periods of limited visibility. Control of power stations enables friendly forces to control, to a degree, background illumination. Shutting off the power to the street lights is much easier than shooting out the lights. Commanders must balance the tradeoff between force protection and maintaining law and order after the battle is over. During cold weather, the control of power stations may be critical to the welfare of the civilian population. d. Identifying friendly units, noncombatant civilians, and enemy troops becomes more difficult during limited-visibility operations. e. Locating the source of sounds becomes more difficult because of the natural echoing in built-up areas and the tendency of sounds to carry farther at night. f. Locating boobytraps and obstacles also becomes more difficult at night. Movement rates are normally slower than during periods of normal visibility. 6. Special Equipment. Fighting during periods of limited visibility requires some specialized equipment to maximize advantages. Military Operations on Urbanized Terrain H - 3