Old Faithful spouts an incredible 20 times a day, blowing at least 3,700 gallons of near boiling water and hot steam skyward with each eruption. Naturalists predict its timely eruption with 90 percent accuracy by observing the previous eruption’s duration and spout height. These stalwart observers use simple tools like a stopwatch and log-book to make their predictions. Old Faithful usually erupts every 74 minutes, but intervals can range from 60-110 minutes. You can find eruption predictions posted clearly around Old Faithful and online.

Yellowstone can be dangerous, but you’ll probably be fine if you stay within posted guidelines. Visitors who stray from the boardwalks around geologic features risk being burned or even killed. The large mammals like bison are wild and will charge visitors who don’t respect their space. Millions of people visit Yellowstone each year without incident by following posted safety instructions. When you visit Yellowstone, pay attention to the signage and warnings from park rangers to ensure you have a safe trip.