Yes, yes, maybe maybe.
Very situational, and dependent on the GM, the world/setting, and the campaign. A blizzard could count as an attack, it could just be environmental damage. The GM might require fortitude saves. Sustenance could counter it, as well as resistance.
Sustenance wouldn’t protect against an actual extraordinary attack though, but resistance could help while in a blizzard I’d say.
Whatever makes the most sense at the time and helps feed the narrative and fit what is happening.