Surfing’s final rounds are underway, thanks to a tropical storm’s waves.

Italo Ferreira of Brazil riding a wave on Tuesday during the men’s surfing quarterfinals at the Tsurigasaki Surfing Beach.Credit...Pool photo by Olivier MorinICHINOMIYA, Japan — The fickle waves at the inaugural Olympic surf competition came roaring to shore on Tuesday, pushed by Tropical Storm Nepartak, leading contest organizers to try to jam the quarterfinals, semifinals and medal matches into one busy day.

The decision to go now was made on Monday night, as the storm churned off the east coast of central Japan, sending swells toward Tsurigasaki Surfing Beach. Surfing’s unique schedule, or lack of one, originally had the contest ending no sooner than Wednesday, but it was determined that…