More than 100 years ago today, a 63-year-old Michigan schoolteacher took the first ride ever down Niagara Falls in a barrel. Annie Edson Taylor may have survived, but the future will tell if the waterfalls available for such (now-illegal) escapades will. Here are a few threats to waterfalls we can’t ignore if we want to preserve these natural wonders.1. DroughtLast year, Yosemite Falls went dry for five months. While the falls have always been ephemeral, meaning they flow seasonally, California’s severe drought had stopped them two months earlier than usual in June until December rains started them again a month late. In The Atlantic, outdoorsman and author Michael Lanza wondered if the world’s sixth-highest falls would actually disappear, with climate change leading to less and less snowfall. Snowpack in the Cascade Range has already decreased 15 to 30 percent in the past 70 years.