You can't drink the water safely, so be sure to bring at least two quarts of water per person on your hike, along with plenty of food. It's an hour and a half for very strong hikers to get to the top. Plan on taking two and a half hours at an easy pace. At least an hour and a half to get down. Looking down the falls.
Avalanche Lake is at the top of the falls.
Now you have to climb down.