Search and rescue crews are scouring the area around Sasamat Lake after a woman with special needs went missing during a daytrip Thursday afternoon.

Twenty-one-year-old Joy Zhang was among a group of nine Douglas College students visiting the lake to celebrate their graduation from a consumer and job preparation program when she and a friend got separated.

The friend, who also has special needs, was found safe sometime after 11 p.m., but authorities say she was confused and could not shed light on Zhang’s whereabouts.

Douglas College president Scott McAlpine confirmed that two teachers were accompanying the class, but did not say whether students are permitted to split from the group.

"Outings are a regular part of the program," McAlpine said. “Right now, the important thing is to do everything in our power to ensure [Zhang’s] safe return,” McAlpine said.

The president said this is the first incident of its kind in the history of the program, which has been operating since the mid-1980s.

Coquitlam Search and Rescue spokesman Dwight Yochim said Zhang, who has the mental capacity of a 10-year-old, and her friend were last spotted together across the lake from the picnic area at around 12:30 p.m. Thursday.

Witnesses described seeing a woman believed to be Zhang limping, leading authorities to suspect she may have an ankle injury.

Her friend was eventually found on a road roughly 1.5 kilometres from the parking lot at White Pine Beach, leaving a large area for search crews to cover.

"The challenge is we don't know what direction she went in," Yochim said. "We've had 25 people out today and a lot of the pulic and we've searched every trail."

Yochim said the best hope of finding Zhang, who doesn’t like to talk to strangers and has no food or cell phone, could be more witness information from the public.

Anyone who believes they may have been Zhang near Sasamat Lake is asked to call authorities.

With a repot from CTV British Columbia’s Brent Shearer