There's a much easier way to get a blizzard to appear. Talk to the Viera on Mount Bur-Omisace (I think her name has Relj or something) during the Fafnir hunt to automatically trigger a blizzard. However, you have to get to smaller section in the Silverflow's End area WITHOUT going through the Frozen Brook area (the place where you fought Trickster). If you go through the Frozen Brook, the weather will automatically change and you will lose your blizzard.

After slaying Fafnir, you won't be able to use the Viera to trigger a blizzard anymore though.