User blog comment:Is that so. Well.../Why I support the Dominion/@comment-1834116-20140312163938/@comment-17114085-20140319123258

Ysgramor and the 500 Companions aren't the ones to blame for the extinction of the Snow Elves. They did started the massacre against the elves, though it continued all the way to High King Harald's time. Harald lived in the 2nd Century of the 1st Era I believe and he is the 13th of Ysgramor's line. So the whole thing took a long time. Also like others have said many Snow Elves went to seek refuge with the Dwemer and accepted the mushrooms that made them blind as one of the conditions. Though the Dwemer tricked them into slavery. Though like the Snow Elf Paladin we meet in Dawnguard said there are secret refuges that could still have Snow-Elf refugees hiding there.