A dispatcher for the Chelan County sheriff's office said late Thursday night that the search for Hildegard Hendrickson would resume Friday morning.
Multiple search dog teams and dozens of searchers have been covering trails in the area.
Undersheriff John Wisemore says a grid search was conducted in a half-mile area around the spot where the woman's car was located.
Hendrickson is a retired Seattle University faculty member and mushroom expert.
Wisemore says fellow mushroom pickers familiar with the woman's methods of searching for mushrooms have also been assisting in the search.
Hendrickson lives alone, and no one knew she failed to return from a day trip until her car was noticed Tuesday at a trailhead.