What to know

• At least 639 people remain stuck in several devastated hydropower stations that have become the focus of rescue efforts, the country's disaster management authority said on Tuesday.S1
• Nepalese authorities say 4,000 people remain unaccounted for as rescue teams with search dogs comb through mud, rocks and debris.S2
• A total of 3,916 people were said to be missing throughout Nepal, the government said.S3
• By Gopal Sharma, Sahana Bajracharya, Liz Lee and Ethan Wang KATHMANDU/BEIJING, Sept 1 (Reuters) - Nepali rescuers built temporary bridges to reach remote areas and dug through the ruins of hydropowerS4