The board settling back onto the water when your speed drops below minimum flying speed and the front wing stops producing lift. A gentle touchdown isn't a crash — it's normal.
Touchdowns are part of learning — the only question is whether they happen under control. The most common trigger is the turn: a tight pivot like a classic tack scrubs so much speed that you drop straight back down. Ride a wide, flowing arc instead and accelerate slightly rather than braking, keeping your weight centred over the board. The second trigger is foot pressure: too much load on the front foot drives the wing under the surface and drops you abruptly, too much on the back shoots you upward. Roughly 60 percent front and 40 percent back is the starting point you fine-tune from. What often gets missed: it's the flinch that turns a touchdown into a crash. Settle, get back to planing, fly again — and if you do fall, fall flat to the side, never backward onto your own foil.