(Gresham, OR)  --  A Gresham man who was considered one of the world's top skiers is dead, following an avalanche on Mount Blanc in Italy.  Dave Rosenbarger, who was known in Europe as "American Dave," was killed in the Friday avalanche.  Rosenbarger grew up in Gresham and was a graduate of Gresham High School and the University of Oregon before making his home in Europe.