Snape + Bigby
That's the plan. They'll probably use some kind of charms to make the area bigger, they've got the guy who controls metal working on the hull, that kind of thing. Snow's efficient. If she wants to make a werewolf prison, you'll get a damn good one.
The ones I hunted down had changed back already. Your werewolves have a distinctive smell, even in the days after changing back, and they couldn't outrun me even if they were turned. They're all dead, trust me.