12 ft. W x 12 ft. D x 8 ft. H Peak-Style Steel Shed-In-A-Box Storage Shed in Grey with Patented Stabilizers

This structure is not totally tight to the outside, and they could just come right in anywhere along the bottom edges.

There are low horizontal framing members along the sides, but not at the front nor rear.

It has a roll-up front door, with zippers down both sides.

It needed a leveled surface for assembly and placement so before we assembled it, my husband prepared the base frame with treated 2X4s and placed it on leveled concrete blocks, used pea pebbles for block base and then assembled the shed on the base. You can place it on grass, gravel, concrete (with cement lag anchors, not included), asphalt or any surface as long as it’s leveled. Since its 8X8, a grading of inch or two would not be a problem.

Not this 8'x8'x8' size unit, but I'm sure they make a ShelterLogic model of suitable size.

you don't have to anchor it if you don't want to... the frame itself if very durable so it would take a very strong wind to blow it over.

Yes, the door has zippers down each side.

They do show pic of animated persons removing snow via a broom.. No required logic required always remove snow from any storage structure. It is rugged but why would you test the tensile strength?

I found it easy enough to assemble, taking me 3 hours to do it alone. A 7/16" socket or nut driver and a step ladder was all that was needed, tool-wise.

The frame is pretty sturdy but hurricane winds will likely destroy it in my opinion.