The heavy clouds forced him to fly lower to follow the creek , which turns into a small valley before its source .
Investigators later concluded that during these final moments before the crash , Ferguson realized he was lost and began following a small creek to the northwest .
The heavy clouds forced Ferguson to fly lower to follow the creek , which turns into a small valley before its source .
Investigators later concluded that during these final moments before the crash , Ferguson realized he was lost and began following a small creek to the northwest .