Nepali government officials confirmed to CBS News that one of the many U.S. nationals missing after flash floods on the Nepal-Tibet border has been contacted. As of Tuesday, about 85 Americans remained listed as missing. In total, more than 4,600 people were reported missing in Nepal, with at least 1,050 confirmed dead. Chinese authorities reported 16 deaths in Tibet and over 550 missing on their side of the border. A document from the Nepal Tourism Board said rescuers had "contact" with five foreign nationals among the missing, including one American, three Spaniards, and one Belgian. Overall, 315 foreign nationals had been rescued so far. CBS News spoke with the only two Americans confirmed to have been rescued from the disaster zone, Anjana Raja and Pattabiraman Venkatesan. The couple from the San Francisco Bay Area were on a pilgrimage to Tibet when the floods struck. They described seeing a massive, dark wave-like surge that they first thought was a forest fire. They escaped their tour bus and climbed to higher ground, spending the night in a goat shed before being airlifted to safety. Approximately 600 hydroelectric power plant workers are among the missing in Nepal, believed to be trapped inside several projects in the disaster area. Search and rescue teams are working to clear mud-blocked tunnels to reach the workers, with concerns about oxygen levels. The disaster was caused by a mountainside and glacier collapse in the Himalayas, which triggered avalanches and flash floods in Tibet and Nepal about a week ago. Recovery teams have found bodies in riverbeds downstream. The Trishuli River, considered sacred in Nepal, reached record levels during the floods. Rohit Tamang, 22, who has lived near the Trishuli River his entire life, described watching helplessly as the waters surged. He said he would not leave his home, as it holds his childhood memories. Nepal’s foreign minister, Shisir Khanal, told CBS News that many foreigners may have been hiking in the mountains when the disaster struck, leaving them stranded without communications but possibly safe. He noted that the region is a popular trekking destination and expressed hope that the number of missing people would decrease as communication challenges are resolved.