Eighteen-year-old Stephen Thomson of Canal Flats, B.C., and 21-year-old Nicholas Hoefnagels of Carstairs, Alta., vanished June 9 while camping at Whitetail Lake.
Searchers later pinpointed an area where a vehicle had veered off a forest service road near the lake and crashed into the rushing waters of Findlay Creek.
RCMP Sgt. Laurie Jalbert said Tuesday the men's families paid for a blasting permit that allowed some rocks to be blown out at the creek, revealing part of the submerged truck.
But heavy rainfall is hampering the search.
"We are headed into 100 millimetres of rain," Jalbert said. "Rain is forecast for this week, which is going to bring the water levels back up and turbidity levels back up again."
Crews have already searched for the bodies downstream and will make another attempt to lower a camera into the vehicle, Jalbert said.
However, she said experts believe the men's bodies are no longer in the truck and that water levels are not expected to decline significantly until much later in the summer.