Searchers continued to comb a rugged provincial park near Thunder Bay on Friday in hopes of finding a missing Toronto woman.

Christina Calayaca, 20, has not been seen since Monday, when she went on an early-morning jog at the Rainbow Falls Provincial Park near Schreiber.

Family members have come to the park to be closer to the search effort and more searchers have joined the large police contingent.

A plane with infrared heat-seeking camera equipment flew over the area Friday, but the equipment didn't work, an OPP spokeswoman said.

"Unfortunately, it appears that because of the type of the terrain that we're dealing with in the area … it was unsuccessful in detecting or assisting in the search," Sgt. Debra Tully told CBC News. 

Search officials have said Calayaca's survival chances remain high despite not having any overnight camping gear.

Calayaca's family has said she is not an experienced camper and had told them that she planned to visit Montreal for a Christian retreat over last week's holiday weekend.