Take on the infamous Zion Narrows. This gorge, with walls a thousand feet tall and the river sometimes just twenty to thirty feet wide, is one of the most popular areas in Zion National Park, according to NPS. It’s easy to hike the park’s slot canyons – when it’s not raining. If a sudden storm hits the area, don’t waste time and find refuge somewhere high. Unexpected and abrupt flash flooding is common year-round.