The resupply of the hill outposts was a particularly hazardous aspect of the overall mission. Approximately 20 percent of Colonel Lownds' personnel occupied these redoubts and, for all practical purposes, were cut off from the rest of the garrison. The road north of the base was not secure and the perimeters atop the hills were too small and irregular for parachute drops; the only way that the isolated posts could be sustained was by helicopter. When the dense monsoon clouds rolled into the valley, the mountain tops were the first to become submerged and, as the overcast lifted, the last to reappear. During February, several of the outposts were completely obscured for more than a week and resupply was impossible. During these periods, the North Vietnamese took advantage of the reduced visibility and emplaced heavy automatic weapons along the neighboring peaks and waited for the ceiling to lift which invariably heralded the arrival of helicopters. As a result, the UH-1Es, UH-34s, and CH-46s were subjected to a hail of enemy bullets during each mission.(126) When the helicopters proceeded to the hills singly or in small groups, each mission was a hair-raising experience for both the chopper crews and the men on the ground. A good example of what often transpired during those frantic moments occurred early in the siege on Hill 881S when Captain Dabney called for a chopper to evacuate a badly wounded Marine. One corporal was assigned as a stretcher bearer because he had a badly impacted wisdom tooth and, once aboard, he could ride out on the helicopter and have the tooth extracted at the main base.[40] Because of the 120mm mortars located in the Horseshoe and the antiaircraft guns which ringed the hill, the men on 881S had to employ a variety of diversions to keep the enemy gunners from getting the range of the incoming choppers. In this instance, they threw a smoke grenade a good distance away from the actual landing zone in hopes that the gunners would register on the smoke and the helicopter would be in and out before the North Vietnamese could readjust. This meant that the helo had about 19 seconds to get off the ground.(127) The ruse did not come off as planned. The stretcher bearers had barely loaded the wounded man aboard the helicopter, a CH-46, when 120mm mortar rounds bracketed the aircraft and spurred the pilot to action. The helo lurched into the air and the sudden jolt rolled the corporal with the bad tooth over the edge of the tail ramp; he held on desperately for a few seconds but finally let go and fell about 20 feet to the ground. Cursing to himself, the young man limped back to his trench and waited for another chance.