Lewis County sheriff Chief Deputy Stacy Brown said the family was off of Forest Service Road 26 about 10 miles south of Randle when they last saw the man about 10:30 a.m.
They waited for him at their car and searched for several hours before calling police Sunday afternoon.
Brown said the man had a backpack with water but was not equipped to spend the night outdoors, where overnight temperatures dropped to about 32 degrees.
The man's family said he is an experienced hiker who does not suffer from any medical conditions that might have caused him to go missing. His name has not been released.
Members of Packwood Search and Rescue and Cascade Dogs searched until midnight and the search resumed Monday with additional personnel.