A pack, which may or may not be a backpack, includes a pack portion made of a flexible material and includes a main interior storage compartment. The pack includes a foldable flap including a front region having an upper portion that, when the foldable flap is unfolded, faces outward and is visible. An aperture, which is included in upper portion of the front region of the foldable flap, is selectively openable when the foldable flap is unfolded to provide access to the main interior storage compartment. The foldable flap can be folded back over itself twice to provide a waterproof barrier against water or other moisture entering the main interior storage compartment of the pack through the aperture. Unlike a typical roll-top backpack, a height of the pack when the foldable flap is unfolded is substantially the same as when the foldable flap is folded back over itself twice.