Concrete, gravel and sand: what the ramp surface tells you

Hard surfaces make up 73% of the ramps that publish one. The rest are the ones worth thinking about before you commit a two-wheel-drive vehicle to a slope.

What each surface does when it is wet

• Concrete slab: predictable, and the only surface that stays predictable at low water. Algae on the bottom third is the usual hazard, not the concrete itself.
• Asphalt: fine above the waterline, soft and slick below it. Asphalt that has spent years submerged often ends in a lip where the mat has lifted.
• Gravel or limestone: workable dry, and a genuine trap after rain. Gravel migrates downhill over a season, so the toe of the ramp is usually the thinnest part.
• Sand or natural ground: assume four-wheel drive and a short wheelbase. A wet sand ramp on a falling tide will strand a two-wheel-drive tow vehicle reliably.
• Plank or timber: usually a small-craft or hand-launch structure, and slick enough that footing matters more than traction.

Where a ramp page shows both a surface and a parking surface, read them together — a concrete ramp reached across a grass lot is a different proposition after three days of rain.