Hopes are starting to dim for a young man, who was swept away in the rushing waters of North Vancouver's Lynn Canyon on Sunday.

For most of Monday morning, a search & rescue chopper was sweeping Lynn Canyon, looking for any sign of a 26-year old north Vancouver man. He and his friends were crossing the river when he slipped and was swept away.

"They made a valiant effort to try to help him, but because the river flow is so fast and the current so strong, ultimately they weren't able to catch him before he was swept downstream,'' said RCMP Corp. Peter Devries.

The search centred on an area just downstream from the dam at the trail head of the Lynn Canyon headwaters. For much of the day, the man's friends hunted and waited, waited and hunted, but to no avail.

The search has been downgraded, but is not officially over, police say.

On Monday, one of the man's friends was still hanging on to hope that he will be found

"Omigod... we're just hoping we're going to get some good news soon...," she said.

But for other friends, it is starting to sink in that the missing man is unlikely to survive in such swift, icy water.

"The river right now is quite high. The last few days of hot weather have caused a heavy snow pack from the mountains. So the river is particularly dangerous right now," said Devries.

On average, 80 British Columbians die from drowning every year. Two or three of those are usually lost here in the canyon, where cliff-jumping is popular.

Even on a day when volunteers, police and park rangers are searching for the missing man, there are still dozens of young people swimming to cool off from the summer's first heat wave.

"Water experts say people who are unfortunate enough to fall into the river should keep their bum down and feet thrust forward. That way they may not hit your head on the way downstream. Then try to grab a hold along the shore and... pray!"

"Be aware of what the hazards are. Stay on the trails. The water level is quite high on all our local rivers,'' said Andy Robinson, a park ranger. "We're just asking the public to be safe."

With a report by CTV British Columbia's Peter Grainger