I have about an inch on roof of 23B. It is also under a tree that is dripping ice and leaves. I had the trailer level but have tilted it to lean forward so ice will run down front when it melts. It...
A square foot of 1" thick ice weighs just under 5 pounds. Your trailer roof is probably 18' x 8' or 144 square feet so there's roughly 700 pounds of ice up there.
Under a tree can result in damage from falling branches, etc.