Thomas Mullarkey, 65, of Richmond hasn't been seen or heard from since he boarded a chairlift last Wednesday morning at Bear Valley. His car was found in the parking lot.
Family members describe Mullarkey as an experienced outdoorsman in good health.
"He's been at this mountain many times," said his nephew, Markus Mullarkey. "We've been snow camping literally at Tamarack right around the corner here."
"So there's still that possibility that he can survive this, and build a snow cave and stay warm enough until we find him," added his niece Rachel Gomez.
Nearly 150 searchers from multiple agencies have been involved in the rescue effort, which is beginning to scale down.
Anyone who may have seen Thomas Mullarkey at Bear Valley is encouraged to contact the Alpine County Sheriff's Office.
He stands at 5 feet 8 inches tall, weighs 150 pounds and has gray hair and blue eyes. He was last seen wearing a blue and green snowsuit with yellow striping on the shoulders.
"A lot of people in the family have said, if there's anybody in the family who could figure out how to weather this and make it through, it would be him," said Markus Mullarkey, who also expressed deep appreciation for the efforts of all the search crews. "But it's tough you know, obviously (for) the family. It's nice we have a very big family, so there's a lot of people up here kinda holding it together with each other as much as we can."