THOUSANDS MISSING: Rescuers search towns devastated by Nepal flooding

O. LOCATE AND HELP AMERICANS WHO. NEED TO BE EVACUATED OR MISSING. >> Julie: JEFF PAUL HAS THE. LATEST. >> THE RISK OF FLOODING IS SO. SIGNIFICANT RIGHT NOW THAT. RESCUE OPERATIONS HAD TO BE. STOPPED FOR SEVERAL HOURS TO. KEEP THE RECOVERY TEAMS SAFE. OPERATIONS HAVE SINCE RESUMED. AUTHORITIES ON HIGH ALERT. WATCHING TWO LAKES UPSTREAM THAT. COULD BURST. NEPAL DISASTER MANAGEMENT. AUTHORITY IS ACTIVE IN WARNING. PEOPLE IN THE LOW LYING AREAS.

WHEN THEY NEED TO EVACUATE. THE MAIN CONCERN SURROUNDS THESE. TWO LAKES. ONE IN NEPAL, ONE IN CHINA THAT. FORMED AFTER THE DEADLY FLOODS. IF THEY DON'T DRAIN, THE LAKES. COULD START OVERFLOWING SENDING. MORE WATER DOWNSTREAM TO. IMPACTED AREAS BURIED IN MUD AND. DEBRIS COMPLICATING AN ALREADY. TOUGH SITUATION FOR RESCUE. TEAMS. THOSE TEAMS CONTINUE TO PULL. SURVIVORS FROM DEVASTATED AREAS. WITH HUNDREDS STILL MISSING IT. ISN'T THE CASE FOR SO MANY.

FAMILIES. >> MY WIFE AND SON WERE TAKEN BY. THE FLOOD. MY WHOLE VILLAGE WAS TAKEN BY. THE FLOOD. ALMOST ALL THE ROADS WERE ALSO. SWEPT AWAY BY THE FLOOD. ALL THE BRIDGES WERE ALSO GONE. >> IT WAS WEDNESDAY WHEN A. GLACIER COLLAPSE TRIGGERED A. POWERFUL LANDSLIDE SENDING ROCK, ICE, MUD AND DEBRIS CRASHING. THROUGH THE HIM -- HIM LAY.

YEAHS. MANY RESCUES ARE RELYING ON. HELICOPTERS TO GET PEOPLE TO. SAFETY. IT DELIVERED I.