Pat Leonard woke to a "sniffing, snuffling, snorting sound" and the sight of something black and furry rubbing against the window of his tent. He had just enough time to bolt upright, still covered in sleeping bag, when the critter cried "Woof!" and was gone.

"A small black bear had been investigating my boot tops as a possible meal," writes Leonard. "They must be starting to smell like something a bear would consider eating. If I get hungry enough they may even start to appeal to me."

That written report comes from Leonard, a 46-year-old Germantown physicist and one of a crew of adventurers canoeing 1,900 miles this summer from the Canadian Rockies to Hudson Bay.

When last we saw our waterlogged paddlers, who range in age from 18 to 53 and in experience from expert to rank amateur, they were camped beside the Athabasca River at Fort McMurray, 15 days and 687 miles beyond the start of the trip and a rough 1,200 miles from its end. They had survived, relatively intact, rapids, rain and the social friction you would expect among strangers faced with the most demanding challenge of their lives.

In the three weeks since, however, this summer adventure has lost considerable ballast. One canoe was swamped. Two of the crew quit and a third was asked to leave.

"I have not felt the same group closeness on this trip as I have on others," said Donna Berglund, the 38-year-old organizer and leader of the expedition.

Don Rabern and Marvel Harrison quit the trip at Fort McMurray, the day after I flew home. The couple had begun the journey with enough enthusiasm to keep the Argentine Navy afloat. But the separate pressures of the trip and their relatively new relationship seemed to wear them down a bit more every day. Harrison, a 26-year-old nutritionist and the only Canadian in this attempt to retrace Canadian fur trader routes of two centuries ago, decided she had used up all the trip's fun tickets in the first two weeks.

"They agonized over the decision and I didn't pressure them," said Donna Berglund in a phone conversation from Stony Rapids, the last outpost they will see until they reach Hudson Bay in four weeks.

The day that began with their departure, got no better as it went along. The remaining five crew members, packed into two heavily loaded canoes, had just reentered the Athabasca when the trip took on more water.

"The whole event had a fascinating air of inevitability about it," writes Leonard, who can make a tornado sound like an event not to be missed. "I looked at the water now lapping over the tops of my boots, looked at the island ahead and judged that we were not going to make it afloat . . . about one minute later we went down by the stern and gently rolled to the right."

The hardest part of the leg from Fort McMurray to Stony Rapids was a 10-day, 260-mile paddle along the northern shore of Lake Athabasca. It was during that portion of the trip that Barry Crouch, the youngest and least experienced of the crew, began to lose his steam.

"We thought at first he was hiding an injury," said Berglund. "He just wasn't keeping up. His mental attitude was showing through. We had a long discussion and Barry agreed that he had lost the thrill and newness of the trip."

When the canoes reached Stony Rapids, the last possible place to leave the journey, Crouch was asked to leave.

"He has grown so much since we started," said Berglund, "but he is just not ready for this trip with this group. One indication of how he's changed was his reaction to being asked to go. A month ago you would have expected . . . a tantrum. Yesterday his reaction was to cry on my shoulder. And that is a warmer, more sensitive person than started this trip. I think that took a lot from Barry."