The 2.2 million acres that make up Yellowstone National Park provide visitors with unmatched opportunities to view wildlife in an intact ecosystem, explore geologic wonders like the Grand Canyon of the Yellowstone, and observe a multitude of hydrothermal features. The park’s geothermal areas contain about half of the world’s active geysers in addition to thousands of other features including hot springs, mudpots, travertine terraces, and fumaroles.
In total, there are an estimated 10,000 active hydrothermal features throughout Yellowstone National Park. Despite the intense heat of the features, microscopic organisms called thermophiles survive and thrive in these habitats. In some features like the Grand Prismatic Spring at Midway Geyser Basin the thermophiles are responsible for brilliant colors. Both these microorganisms and the features that surround them are extremely sensitive and close-up interactions with humans can cause irreparable damage.
Yellowstone’s hot springs and hydrothermal features are often dangerously hot as well. Some waters sit around 145°F, while some geysers can erupt with temperatures of 200°F or above. At these near-boiling temperatures, fatalities can occur within a short period of time.
For these reasons, Yellowstone National Park requires visitors to stay on boardwalks in hydrothermal areas, but some tourists have a hard time following the rules. This person, for example, was spotted walking off-boardwalk among hydrothermal features along the Fountain Paint Pots Trail in the Lower Geyser Basin while another took pictures of them approaching an actively erupting geyser.
Fortunately it appears that nobody was hurt in this incident but a slip or fall in the wrong direction could have easily led to injury or death. Cases where tourists are caught leaving Yellowstone’s boardwalks in hydrothermal areas can end in charges with punishments including fines and jail time. In 2020, two men were sentenced for trespassing on the cone of Old Faithful Geyser, each receiving 10 days of incarceration, $540 in restitution, 5 years of unsupervised probation, and a 5-year ban from Yellowstone National Park. Read more on safety in thermal areas below.
Yellowstone National Park Thermal Safety:
Boardwalks and trails protect you and delicate thermal formations. Water in hot springs can cause severe or fatal burns, and scalding water underlies most of the thin, breakable crust around hot springs.
- Always walk on boardwalks and designated trails. Keep children close and do not let them run on boardwalks.
- Do not touch thermal features or runoff.
- Swimming or soaking in hot springs is prohibited. More than 20 people have died from burns suffered after they entered or fell into Yellowstone’s hot springs.
- Pets are prohibited in thermal areas.
- Do not throw objects into hot springs or other hydrothermal features.
- Toxic gases may accumulate to dangerous levels in some hydrothermal areas. If you begin to feel sick while exploring one of our geyser basins, leave the area immediately.
