[picks drywall]

i would cover those vent holes if mine. but ive never seen anything like that around here. im thinking thy are letting in too much cold air from wind(cold air dont rise). if they dont have screen already maybe some fine screen would cut down on the flow. strange set up there so im only guessing. lol

 

[picks drywall]

now sell them! lol good job!

id still use some scratch pad or piece of old furnace filter behind it. if wind "piles up" there is creates "atmospheric pressure" and forces air to least resistance. the scratch pad or filter material will help with that.