Pver, first of all, I sincerely empathize with you and all of the others affected by these massive storms. In regard to your immediate concern, there is no way to say, one way or the other, without at least pictures, but I will try to give you some basics. First and foremost, based on your question, I am going to assume that you do not have much experience on a roof, but regardless, safety is always first. Please be careful. No amount of potential water damage is worth a broken limb, or worse. If you have a large area of damaged or removed shingles, as you can imagine, a tarp can provide good short term protection. The keys are to make sure that it extends over the peak, so that water does not get under it, and to adequately secure it in place. Inexpensive clothesline rope will be fine until the roofer gets there. Depending on your situation, you can tie off to stakes or heavy objects on the ground, or to sand bags on the roof. Just make sure that the tarp is spread out fully, so that it does not trap water, and force a backup someplace. If you have say a dozen or so shingles that are pulled away, in various areas of the roof, quite frankly, again, assuming that you have minimal experience on a roof, you may want to opt for playing the odds, and lettting them go. If you wish to repair them though, you can use felt or tar paper, regular shingles, or step flashing. Tuck them under the shingle above the damaged area, and hold the patch in place with a couple of rooting nails. Normally, exposed nails on a roof are a bad thing, but they are fine to get you past the current situation. Hopefully this makes sense, but if you have any questions, come on back, and I or someone will try to assist. Good luck.