American pole-vaulter (pole vault), the first to attain 15 feet (4.57 metres) and the last to set major records with a bamboo pole.

Warmerdam, who was of Dutch ancestry, began vaulting at age 12, using the limb of a peach tree. A graduate of Fresno State College and Stanford University, he taught physical education and coached track and field at Fresno State (later California State University at Fresno). On April 13, 1940, at Berkeley, California, he first achieved a vault of 15 feet. Using a bamboo pole, he established a world outdoor record of 15.6 feet (4.77 metres) on May 23, 1942, at Modesto, California. Few other athletes have so dominated their sport. Warmerdam cleared 15 feet or higher on 43 occasions before any other person performed the feat once. He won the U.S. pole-vault title continuously from 1937 to 1944, except in 1939. In 1942 he received the Sullivan Award as the best American amateur athlete. Regrettably, World War II deprived him of the opportunity to compete in the Olympics.

Warmerdam retired from pole-vaulting competition in 1944, and his records stood for several years. Not until January 27, 1951, did Bob Richards (Richards, Bob) become the second man to vault 15 feet. Don Bragg (Bragg, Don), who used an aluminum pole, broke Warmerdam's long-standing outdoor record on July 2, 1960. Warmerdam continued to vault into his 60s.