Waves on the lake were 4 to 5 feet high Sunday afternoon, making it impossible for divers to go into the water. Instead, crews searched Sunday night by air and by boat.
The missing teens are identified as 14-year-old Scott Hoover and 17-year-old Lorenzo Greer, both of South Bend, Ind.
Hoover's father was able to reach the boy at one point, but couldn't hold on to his son.
The search will continue throughout the night, but a spokesperson for the Indiana Department of Natural Resources calls it a recovery effort.