Heavy snow and rain forced the United Nations to ground its lifesaving relief flights to Pakistan's earthquake-hit areas for a second straight day Monday, as former U.S. President George Bush arrived in the country to begin a tour of the stricken region. Meanwhile, Pakistani officials said fresh landslides have blocked roads leading into the Neelum and Jhelum valleys in Pakistani-administered Kashmir, where hundreds of thousands of survivors remain heavily reliant on aid groups for food and shelter. Some 87,000 were killed and another 3.5 million made homeless by the 7.6 magnitude tremor on Oct. 8. U.N. spokesman Ben Malor said relief flights were supposed to resume Monday, but an extended cold front prompted their cancellation. "We are watching the situation every moment to see when we can (resume)," he said. The U.N. flies aid to 186 different sites in the quake-affected area. Dr. Sardar Mehmood Ahmed, Muzaffarabad's district health officer, told the AP that there were nearly 4,000 respiratory infection cases reported last week. Three people died but the number of cases didn't reflect a spike from last year, he said. Ahmed Salman, an Information Ministry official, said former President Bush arrived in Pakistan on Monday morning for a two-day visit. U.S. Embassy officials said Bush was scheduled to meet Pakistani President Gen. Pervez Musharraf. They would not divulge more details due to security concerns. On Tuesday, Bush is scheduled to fly to Kashmir, and is likely to tour tented villages and meet aid workers.