CANMORE, ALBERTA, FEB. 20 -- The string of U.S. disappointments in this XV Winter Olympics continued today as the man considered North America's best hope for a medal in biathlon, Josh Thompson, flopped in his best event, the 20-kilometer race won by East Germany's Frank-Peter Roetsch.

Thompson, skiing in balmy, 52-degree weather on snow that ran from grainy "corn" to slush in the shadow of the Rockies, missed three of his final five targets in the shooting portion of the competition and wound up 25th of 71 starters.

It was a dispiriting result for the 25-year-old Coloradan, whose second-place finish in the 20K biathlon world championships in Lake Placid, N.Y., last year convinced many he could bring the United States its first Olympic medal in the arcane European sport, which combines cross country skiing and rifle shooting.

But Thompson's eyes were red-rimmed at the finish and he strode off without a word. Reporters caught up with him later at a ski-waxing shed, where he said he wasn't done.

"There's another race in three days {the 10K, in which he also is entered}," said Thompson. "I'll go home and kick the wall and go out and try again."

Thompson's overall time of 1 hour 1:29 minutes was almost five minutes off Roetsch's winning time, 56:33.3. Thompson's total included five one-minute penalties for missed shots; Roetsch had three misses in his 20 shots.

Roetsch, top-ranked in World Cup competition, won three gold medals at last year's worlds, a silver at the Sarajevo Olympics in 1984 and was the favorite here.

Russian Valeri Medvedtsev was second in 56:54.6 with two penalty minutes and Italy's Johann Passler took the bronze in 57:10.1, also with two misses.

Thompson was best of four Americans entered. Teammates Darrin Binning, Willie Carow and Curtis Schreiner were 42nd, 49th and 52nd, respectively.

Thompson was in the running for a top-10 finish until his fortunes blew away in three puffs of smoke on the last of four stops to shoot at targets from 50 meters away. Biathletes shoot five bullets at a time, twice from prone positions and twice standing, each time at the end of a skiing run.

Thompson had only two misses going into the final round. But shooting from a standing position in front of a crowd of onlookers in the main grandstand, he missed three times.

"That pretty much sealed it," he said later. "The day wasn't going well. I said, 'Okay.' But then I did it again. It's real disappointing when you don't put it {the bullet} in the middle."

Thompson took plenty of time on the final round of shooting, but couldn't dial in the target. He said he'd experienced trouble like that before, "but I was never on a pedestal like this. It was a long fall."

In an interview last week, Thompson said shooting would be the key here because so many top competitors were close to equal in skiing, and the course was challenging but fair.

But today's melting snow was no help to him. Carow said Thompson's late start, No. 57, made him more vulnerable to slushier conditions than those who started earlier.

Conditions were unusual for February in the Canadian Rockies as a warm sun beat down all day. Carow said the weather made for inconsistent snow conditions that were hard to get a handle on: slushy in exposed valleys, hard and grainy in the woods.

"The people who started toward the end might have had problems with their skis," Carow said as he stood hatless and jacketless in the sunshine after his race. "We knew it was going to be warm, but not this warm."

Roetsch, who started No. 43, agreed the snow was inconsistent on the course, but said it didn't deteriorate during the day, "and it was the same for everyone."