The search for a senior missing in the wilderness near Cultus Lake is now in its fourth day, and there’s still been no sign of the woman.

About 30 volunteers from search and rescue groups across Metro Vancouver and the Fraser Valley have been carefully canvassing the dense brush for 82-year-old Valentina Kushnarova, who set out from from Frost Road to go mushroom picking on Thursday.

The primary search area is just about one square kilometre, but volunteers don’t know which direction Kushnarova went after leaving home.

Kushnarova lives her with extended family at the end of Frost Road south of Cultus Lake, not far from the US border.

According to her family, she’s relatively fit and knows the area well, frequently venturing into the wilderness alone.

She’s been missing since Thursday and the urgency builds with each passing hour.

“The survivability at this length of time is not great. It doesn’t mean to say we’ve given up hope. Far from it. But it just means it’s all the more difficult,” said Search Manager Neil Brewer with Kent Harrison Search and Rescue.

On the first two days, RCMP searched from the air, but the thick tree canopy made it difficult for them to find any clues.

The forest floor is also dense with underbrush, so searchers are spacing just three metres apart as they methodically comb the area.

“As you can see from the map right now, it’s just absolutely obliterated with searcher GPS tracks,” said Brewer as he monitored search teams in real time from a mobile command centre. “So, once we got to this point, we’re now expanding the area to what originally would have been low probability areas.”

Kushnareva is about five feet tall with short grey hair and blue eyes.

Now four days missing, volunteers fear she may be injured and unresponsive to their shouts and whistles, making the search through the dense underbrush that much more challenging.