RIO DE JANEIRO – During Wednesday's seeding run, Alise Post got a taste of the tricky winds at the Olympic BMX Centre. The St. Cloud native saw Thursday how much of an effect that could have on the semifinals and finals.

Three top riders crashed in the men's quarterfinals, including two-time Olympic gold medalist Maris Strombergs of Latvia. Strombergs did not make the semifinals, and he joined other riders in calling the wind a major factor in the outcome. Strombergs said the tailwind on the first straightaway is "the complete opposite'' of what riders want, and he suggested the design of the track contributed to several crashes as the men's competition began.

Post is among 16 women who will compete in the semifinals Friday. She finished her seeding run Wednesday with the eighth-fastest time, 35.509 seconds, while teammate Brooke Crain was seventh (35.345). Post will compete in Heat 1 in the semifinals, and Crain will be in Heat 2.

The riders in each heat complete three runs of a 400-meter course studded with jumps, bumps and hairpin turns. The top four from each heat move on to Friday's finals. World champion and 2012 Olympic gold medalist Mariana Pajon of Colombia led the qualifying with a time of 34.508.

During Wednesday's seeding run, Britain's Liam Phillips said the track was "really, really fast'' and that even one small mistake could be disastrous. Sam Willoughby of Australia, Post's fiancé, said it was particularly important to get an early lead Thursday to avoid "the carnage out there.'' U.S. rider Connor Fields noted the wind changed direction from Wednesday's seeding runs, and a strong headwind in the second straightaway made the jumps feel longer.

There will be a viewing party to watch Post's races at the Marcus Parkwood Cinema in Waite Park. The semifinals start at 11:30 a.m. Twin Cities time, and the finals start at 1 p.m.

Rachel Blount