Slides out, they are designed to keep the water out. We got 28" in one night while in Gulf Shores. Flooded but didn't have any real issues. Only caution I would give is if you don't intend to move your rig for a few weeks, make sure the brake pads don't get stuck to the rotors. As for the toppers, the only time I lost mine, and I lost all four was when a tornado passed over us in Matagordo Texas. I was fortunate as my neighbor's fiver was picked up and deposited on the grass next to his pad. Another 30' fiver flipped four times injuring all three inside.....be safe....Dennis