RE: Malibu Rapids (4 knots of current) | Princess Lousia Marine Park

You know what... I actually had the same experience there one time. I heard something that sounded like an avalanche, or a really low flying jumbo jet. It turned out to be an ice dam breaking, high in the mountains. I could see one of the waterfalls way up in the back left of the mountains swell up, way bigger than it was before. I kept waiting for the water to come gushing out of the waterfall at the waters edge but it never did. Maybe that is what happened to you...would make sense with all the rain.