There is an innate perversity in humankind that accounts for a lot of foolishness and sometimes it seems to run strongest in white-water canoe paddlers. Come spring and, like salmon, we return to the rivers in spite of all obstacles.

That, more or less, is how we got to the Casselman Riber in Pennsylvania, in the midst of a March snowstorm.

It had been warm all week and when we left Washington early in the morning the temperature was well above freezing. By the time we reached Cumberland, it was snowing and every foot we climbed into the mountains from there brought more snow and stronger winds. When we turned north into Pennsylvania, snow seemed to fill all the space around us.

"I don't believe this," I mumbled dumbly to my husband.

"We'll probably call it off," he predicted as we drove through Confluence where a bank sign flashed "30 degrees." "It's awfully cold to be paddling a river as rough as the Casselman."

We'd had a chance to cancel back on U.S 48 when John Schaub pulled onto the shoulder to retie canoes shifted by the wind. Instead, we had waited in our separate cars until he finished and the convoy moved on.

Pennsylvania Route 281 is narrow and lined alternately by stands of hemlock and open farmland. The boughs of the trees were heavy with snow and bent over the roadway, obscuring the view. Where the road was open between the farms, it was difficult to pick up the outline of the blacktop. The lead vehicle was a four-wheel drive truck though, and the rest of us had snow tires so we kept moving, and each mile we drove seemed to make the next mile inevitable.

We stopped at Fort Hill to leave a car so we could cut the 12-mile river trip short if we chose. Still there was no real discussion of canceling. Perhaps it was because down there, in the protected river gorge, the snow was falling straight down, gently, and it did not seem so thick or so cold. Besides, we could see the river, hear it, almost feel it.

The closest we came to calling it off was at the river, where we meant to put the boats in the water. After finally getting there, we couldn't find a place to park the cars.Except for the small steep river access, all the land was posted "No Trespassing." We'd parked along here before without trouble; the signs had to be recent. We knew we could park the cars back on 281 about three miles away, but we needed to bring back one car with drivers.

Marcie Campbell, designated trip leader, walked over to a nearby house and asked permission to park one car. She was refused. No one answered at the other house. Obviously, something had happened that made the local people angry with canoeists. It's beginning to be a common story and a frustrating one for the organized canoe clubs which made respect for both property and owner a matter of policy.

Just at the point of decision, along came the cavalry in a VW bug. Bill Rosenthal lives in Warren, Ohio. As he tells the story, many years ago when he was a novice paddler, Ken Campbell had taken him under his wing on a river trip. Bill rarely paddles anymore because of his health, but when he hears the Campbells will be as far west at the Casselman, he drives over from Ohio just to say hello.

Bill offered to shuttle all the cars for us. The Lone Ranger, out of Ohio.

It was settled, and we began to unload boats and gear. Sheets of snow covered the gear as quickly as it was unloaded. The snow was thick again, like flakes of popcorn. We had to shake it off our life jackets and out of our helmets before we could put them on. Paddles, mostly white, disappeared when put on the ground.

Most of the six open canoes in the group had canvas or orlon decks which snapped over the hull to keep excess water out and warmth in. Cold fingers made snaps hard to secure and there was much grumbling.

Finally everything was lashed in, tied on or snapped down and it was a ridiculous sight. The flotilla was a splash of gaiety in a gray landscape: yellow, red, green and black canoes, with green and white cloth decking; blue, green and silver saddle jackets beneath red, orange and blue life jackets. Somebody made a comment about needing a little color coordination in this group.

As Tom and I pushed off into the river I felt a surge of relief. In spite of weather, parking, even reason, we would paddle this river today.

We had been on the Casselman twice before. Both times the water level had been much higher than it was now and both times Tom and I had been rudely dumped from our canoe by the river. It had taken us two years to get back to exorcise that devil. Curiously, neither of us was as tense about this trip as about those. We were ready for a chance to right our balance of confidence with the Casselman.

But it didn't matter. Because of the lower water level, it was a different river. Changes in water levels bring drastic changes in the character of a river. Rocks appear and disappear; holes and hydraulics, even whirlpools, appear where none were before.

At lower water, the Casselman is far less ferocious and pushy, far more technical. We worked our way back and forth through the rock gardens, searching for a passage. They are called rock gardens because rocks seem to grow up in front of you just where you had meant to go.

Instead of pushing forward to crash through heavy waves, we backpaddled to slow down while we puzzled out our next move or to ferry laterally back and forth across the width of the river to look for the one place where we could slip a 17-foot long, 36-inch wide canoe over a ledge.

At one point, when we were sitting in a quiet spot, resting after one of those mazes, John and Judy Schaub pulled in beside us. "On a day like this," John declared, "I know how crazy I am."

In his black boat, dubbed the Black Hole, dark paddle jacket and dark wool hat pulled down over his face, John looked like the Lord High Executioner.

With all the maneuvering, we had worked up a sweat inside our rubber wet suits by lunch time, in spite of the temperature and the continuing snow.

As I climbed from the boat though, I noted that all the water collected on the decking had turned to slush. Marcie Campbell complained that her kneepads had frozen to the bottom of her boat. Paddles and gloves showed traces of ice and ropes on the ends of the canoes were frozen in place. We all had cold feet.

Though we built a fire, most of us got colder standing around at lunch than we had on the river. It occurred to us later that the air was getting rawer and the wind was picking up.

Shortly after lunch, we reached Railroad Rapid where Tom and I had dumped in 1979. I could still remember the shock of the cold water and not being able to breathe with waves hitting me in the face. I remembered plunging over the ledge above the bridge, looking up at water closing around me and being angry with myself.

After we passed the bridge in the snow, muscles in the back of my shoulders and a knot in my stomach I didn't know was there, relaxed.

The wind began to whip sideways and make the boats hard to control. The snowflakes were smaller and stung as they smacked against our faces. Judy Schaub wondered if there were such a thing as acid snow.

In the middle of a long, complex rock garden that we remember as "the exhausting rapid," Tom started yelling at me to pull in somewhere. "I can't see a thing," he complained as he scraped a glaze of snow and ice off his glasses.

When we reached the bridge at Fort Hill, every single boat pulled in to shore. Half a trip was better than none and infinitely better than a whole one on a day like this.

We'd planned to stay the night in Cumberland and run another river the next day. At breakfast, Marcie Campbell asked if we wanted to paddle the second half of the Casselman.

The temperatures then was about 20 and there was still snow in the air. One by one we declined.

Even salmon have to conserve their strength.