The 70-year-old Sykes was reported missing Wednesday after she and her hiking partner decided to split up and meet back up that night.
Sykes' hiking partner, her boyfriend, said the pair encountered snow at about 4,500 to 5,000 feet up the mountain and since he wasn't experienced hiking in snow, he turned back.
Officials found a body near the Owyhigh Lakes Trail on the east side of the mountain Saturday, though its identity was not confirmed.
"It's really steep, rough terrain that's not easy to travel in," said Mount Rainier spokeswoman Patti Wold. "Hardly anyone goes there."
The body was being evaluated by the Pierce County Medical Examiner.