Well, if you are 1950 I have a few years on you (and DH has a few more than that!)
Don't despair. There are ways to boost the shedding power of your tarp.
When I first started with the tarp I tried using a stiff wire sub-strata but it held snow. It was flat so rain/snow just sat in the tarp and I had to bail it out. (Why is frigid water in the dead of winter so much heavier than warm water in the summer??)
Sooo, I cut some plywood triangles and placed them along the wire. I covered them in rags so they would not cut the tarp. This worked better.
The final boost was to drill a hole at the peak of each triangle and put a dowel (actually a bamboo pole) as a support under the tarp. That worked like magic for the entire snowy winter!
What I was going to do next was use the triangles to support the wire I had previously used flat, but we opted for the frames you see in the pictures.
My 2017 project will hopefully be to reinforce the side walls to hold weight then roof the run with a permanent roof. We shall see how I feel.