(CNN) A pair of 16-year-old snowboarders lost in the wintry Canadian wilderness kept warm until their rescue by building a fire -- and using their homework as kindling.

The teens didn't return from the slopes at Whitewater Ski Resort in Nelson, British Columbia, so a 10-member volunteer team of Nelson Search and Rescue set out to track them down before nightfall.

That didn't happen.

The squad patrolled the roads overnight, flashing lights and sirens to attract the boys before weather worsened, but they were nowhere to be found, Nelson Search and Rescue said.

Search efforts resumed Monday morning with a helicopter scanning from the air. Finally, rescuers found the boys in a valley south of the resort.

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