Trent Nelson | The Salt Lake Tribune A mammoth waterfall outside of St. George, formed by rainwater, Wednesday, December 22, 2010.Trent Nelson | The Salt Lake Tribune A mammoth waterfall outside of St. George, formed by rainwater, Wednesday, December 22, 2010.Trent Nelson | The Salt Lake Tribune A mammoth waterfall outside of St. George, formed by rainwater, Wednesday, December 22, 2010.Trent Nelson | The Salt Lake Tribune A mammoth waterfall outside of St. George, formed by rainwater, Wednesday, December 22, 2010.Trent Nelson | The Salt Lake Tribune A mammoth waterfall outside of St. George, formed by rainwater, Wednesday, December 22, 2010.Trent Nelson | The Salt Lake Tribune A mammoth waterfall outside of St. George, formed by rainwater, Wednesday, December 22, 2010.Trent Nelson | The Salt Lake Tribune An enormous waterfall fed by rainwater NE of St. George. Aerial views of flooding in St. George, Wednesday, December 22, 2010.