You have a bear canister, right? So that's where the food and smelly stuff marmots are interested in goes. Leave it somewhere in the shade, but not in the tent to reduce the temptation. I wouldn't hesitate to leave the tent unzipped, or back packs open, for that matter. If you're really expecting bad weather, you're not going to be heading for the summit anyway, right? Besides, if your tent has a fly, they can crawl underneath it even if it is zipped. If they can't, then leaving it partially unzipped still won't threaten the dryness of your sleeping quarters. That you can leave wide open.