A woman skier died while stranded with her husband in rugged backcountry for days, and Canada's national police force admitted Thursday that it did not react to initial reports of an SOS signal stamped out on a mountainside.

A Royal Canadian Mounted Police search-and-rescue center didn't begin combing the area until a week later — after a passing helicopter spotted Gilles Blackburn, 50, signaling for help. It was too late for the man's wife, Marie-Josee Fortin, 44, who had already died.

Cpl. Dan Moskaluk said officers did not search the area after the first report of the SOS marking because the nearby Kicking Horse ski resort said it didn't know of any missing or overdue skiers.

"There's an error on the part of the RCMP for not initiating a callout on Feb. 21," Moskaluk said.

Blackburn was treated for frostbite, but an autopsy was pending to determine the cause of his wife's death.

According to Moskaluk's account, the Quebec couple became lost when they skied out of bounds from the ski resort Feb. 15. Two days later, an off-duty ski guide touring in the area spotted tracks and an SOS stamped into the snow.

The guide contacted his employer, Purcell Helicopter Skiing, which told the resort. The resort informed search-and-rescue officials. No search was launched because resort and rescue officials didn't find any indication of unreturned rental skis, missing persons reports or vehicles left in the parking lot.

On Feb. 21, skiers saw two more SOS symbols and notified Purcell, which this time reported it to the RCMP.

But it wasn't until a heli-skiing tour spotted Blackburn waving his arms for help Feb. 24 that police acted.

Temperatures in Golden ranged from a high of 41 Fahrenheit one day to a low of zero F overnight during the period the couple was stranded.

Moskaluk said an independent review would investigate why police didn't search when the SOS was first reported.