The 21-year-old Karelin was Russia’s best hope for a medal in ski jumping at the Sochi Olympics in 2014.
Karelin made the podium three times in 79 World Cup events — most recently a second place in Garmisch-Partenkirchen, Germany, on Jan. 1. He was 23rd in the final World Cup standings last season.
Karelin’s best result at the Vancouver Olympics a year ago was tenth place in the team event. He also took part at two world championships.
The accident occurred early Sunday in Karelin’s hometown of Nizhny Novgorod, about 400 kilometers (250 miles) east of Moscow.