When building dirt jumps, it helps if it rains, or you need to water them, because the water washes all the dust and pebbles that won't stick together out, and then helps the rest of the dirt solidify, a little bit like mixing concrete. Eventually the dirt gets so hard packed from riding it that the take-offs will pretty much shed water. If it rains hard, all the features need is a day or so of sun to dry out enough to ride, and they won't really lose their shape. I'm assuming that would be the case with this half pipe item.
That's a sick edit, but they could have gone easy on the slow-mo, I think.
Don't mind me.