It would be 'very difficult' for missing 79-year-old San Mateo Co. woman to still be alive: sheriff

PORTOLA VALLEY, Calif. (KGO) -- The San Mateo County Sheriff says it would be "very difficult" for the hiker who went missing earlier this month to still be alive.

Margaret "Elaine" McKinley, 79, was last seen May 1, hiking along the Lost Trail in Windy Hill Open Space Preserve in Portola Valley. She was wearing a red jacket and black pants when she went missing, during a hike with friends and family, after she went ahead of the group.

The search for her picked up again this weekend, with 100 volunteers back out to search the area.

"We are hopeful, but we do understand that, you know, it's been almost two weeks, and it would be very difficult for any, any person to stay alive during this period," said San Mateo County Sheriff Christina Corpus.

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More than 600 volunteers have helped search, including drones and K-9 units and mutual aid from nearby counties.

Corpus says with this many people looking, it's concerning that there have been no confirmed sightings or discovery of her items.