4. Heavy dust or loose snow conditions interfere with the vision of the pilot Just before touchdown. This effect can be reduced by clearing, wetting down, or using improvised mats. 5. Landing pads may be prepared on swamp or marsh areas by building platforms of locally available materials (Figure 16). Such LZs are normally used for daylight operations only. The size of the clearing for this type of LZ is the same as b above, with the following additional requirements for the platform: