Urgent!! Can this dog be kept in the yard?

Found a dog earlier today sitting on my door step. He's a VERY LARGE(100lbs+) Husky/Shepherd Mix. I have a 14 weeks lab puppy in the house and unless absolutely necessary I'd like to keep the dog outside until he is check by a vet or someone claims it(have done what's necessary to find the owner). I live in New York, tonight's temperature is LOW 15F, HIGH 21FWill the dog be okay left outside? Thanks.I gave him a a bunch of towel and a old jacket for bed. He is currently sleeping on the deckshould I build him a dog house? is 6PM right now =X and he's hugedam i'll bring him inside... he's water froze =X****dog belongs to my neighbor's cousin, ran away from their house to meet my neighbor's husky... heck