When at flood stage, water will be falling from one end of channel at the top to the other. The feeling when looking at the falls during flood stage is one of reverence as you can very easily see that being anywhere near the bottom would put you in extreme danger of being crushed. So if for some reason you decide to hike down there stay away from the falls themselves or you might become part of them. It will also be very slippery as the mist will have covered all the rocks with a hefty coat of water.
Be careful with the flash on your camera. The flash will catch the mist coming up from the falls. They turn out as shiny blobs and ruin your photos.