This is a sign at top of Vernal Falls. Notice lower, right corner: If you slip and go over the waterfall, YOU WILL DIE

Matter-of-factly put. 

Crystal clear pools at the top of Vernal Falls will entice you - especially on way back down, after you've been hiking all day, and are hot, sweaty, smelly, dirty, dusty, tired. Like swimming in a rooftop pool, it's easy to see how someone could get lured into taking a quick dip here. 

The flow is gentle at the top. But the riverbed is slippery. Can hardly stand up without slipping & falling (I know). Wouldn't take much to get you going with the flow - and if you start, prolly wouldn't be able to stop. If you go over the falls, you will fall for a long time - plenty of time to think about what a stupid idea it was to to swim near the top of the falls. 

I have actually scoped this out. If you *do* find yourself getting sucked over the falls, and you can't stop (prolly wouldn't be able to), you want to be to your right (facing downstream), and launch out - as far as you can. Cuz there are gnarly rocks to the left & close to the falls. But the falls are vertical, and there's a deep pool at the bottom. To the right of the pool is a deep part. Might be able to survive if you stay right and launch strong with a powerful jump at the last moment (got nothing to lose at this point, right?) I think the falls are like 350-feet, so you'd be falling over the length of a football field. 

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