On a Sunday afternoon in the resort community of Ketchum, Idaho, more than 600 African-American skiers paraded into the town square, dancing to Tom Browne’s “Funkin’ For Jamaica.” A DJ shouted the names of dozens of black ski clubs, each sporting matching parkas to signify the different cities from which they hailed.

But as the annual gathering of the National Brotherhood of Skiers kicked off on March 1, few realized that 650 miles away, the country’s first reported death from the new coronavirus had just occurred near Seattle....