Angmar is attempting to use dark powers to call forth a blizzard to freeze Evendim.
The first canyon is ahead. To proceed forward, you must claim it.
The second canyon is ahead. To proceed forward, you must claim it.
The third canyon is ahead. To proceed forward, you must claim it.
The Angmarim Sorceror is performing his ritual in the cave ahead. He must be stopped if Evendim is to be saved.