If its going to be that hot... take ingredients to make jerky. The pack out will be much lighter as well.
The only way you'll be able to keep meat in those temps will be by submersion, and even at that the water will probably be in the 60deg range? Big rocks also work as a heat sink to suck the heat out. Shaded rocks partial submerged work really well for this. You can't leave the meat in a plastic bag for too long, or it will go sour. You'll want to pull it out and let it air dry/cool at night or as soon as it cools off.
Will it really be that warm in the mountains? Temps are generally a lot cooler at elevation and along rivers/streams.
You need to get the heat out of the meat as soon as possible and let it crust over. Apply/spray on citric acid, and make sure to use quality game bags. Wash/dry them if they get bloody. You want maximum air flow through the bags. Don't get cheap cheese cloth bags or use cotton sheets. The cheese cloth bags are obviously not a good choice where you have a lot of dust/dirt and blow flies, and cotton will not dry out or breath as well as a good synthetic bag like Caribou Bags, TAG bags, or various other copy cat bags.
Moisture + heat = bacteria.
Citric acid is not a preservative, but reduces the growth of bacteria. You'll want to re-apply daily. I would imagine the blow flies will be pretty bad if its that warm. The citric acid works pretty well to keep them away, but get the meat in game bags asap. I usually soak my game bags in a concentrated solution of citric acid and water, and let them hang to dry. This way I have some protection from the flies right at the start.
Also the flies will be attracted to the nose/ears of the cape/head as soon as the sheep dies. Within minutes. You must cape it, turn eyes, nose/ears, flesh it and salt it at these temps. Pay special attention to the face and areas with short hair, it will slip easiest. Talk to your taxidermist about this.