The head of the U.N. refugee agency said Thursday he was concerned about the fate of more than 40,000 highland quake survivors expected to flee their mountain villages as the frigid Himalayan winter hits, while a NATO official said troops were racing against time to get aid to the most vulnerable. U.N. High Commissioner for Refugees Antonio Guterres urged local officials and the international aid community to urgently prepare for the arrival of thousands of people fleeing harsh conditions and said the world must ensure villagers who choose to remain in the ruins of their shattered homes get the help they need to survive the next few months. "We are doing our best to ensure that everybody, even in the most remote locations, gets enough support to face the winter and to get through the winter without tragedy," he said. Guterres met with Sikander Hayat, the top official in Pakistani-held Kashmir, then flew over and through the quake zone. "It is absolutely awful," he said, looking out from a hillside over the rubble-strewn remains of the town of Balakot, which was largely flattened by the 7.6-magnitude quake. "I have no words to describe my feelings. I don't ever remember seeing a disaster of these proportions." Guterres visited a refugee camp near the northwestern city of Balakot. Hayat said the government expects more than 40,000 people from towns and villages above 1,500 meters (5,000 feet) to descend to the regional capital Muzaffarabad once the weather worsens. On his part, Air Commander Andrew Walton, head of NATO's relief team in Pakistan, said providing food and medicine to people in high mountain villages was "a race in all senses of the word" before winter snow sets in and cuts off communication links. He told a news conference in Islamabad that an estimated 35,000 people at high altitudes are at risk from extreme cold in Bagh, one of the worst-hit districts in Pakistan's part of Kashmir where NATO troops are operating. NATO troops have provided shelter to some 29,000, and efforts are under way to get shelters for the remaining 6,000, Walton said. In Muzaffarabad, a Pakistan army spokesman sounded a positive note, saying military helicopters have stocked outlying regions with enough food, blankets and other necessary items to last through the winter, when flights likely will be hampered by bad weather. "We are all set for the winter," Maj. Farooq Nasir said. "We have stocked tons of food, thousands of blankets and other necessary items which will be sufficient until February."