Auction.com Tree through roof, but haven't closed yet

[Shannon Cannon]

I just won a house on auction.com a couple weeks ago. Both I and the seller have signed the contract but haven't closed yet. I drove by the house today, and a large tree limb is sticking straight out of the roof! It's hard to tell if it's completely through the ceiling or not. We are forecasted to get a good bit of rain next week with Hurricane Harvey remnants, and not sure how the house will be affected. I was going to replace the roof anyways, but there will be some additional expense I hadn't planned on. It's still a good deal regardless, but how does this work, since we haven't closed yet? Can I call them, let them know about the tree, and ask them to reduce the price? Have any of you encountered a similar situation? Appreciate your help! 

Shannon