Many of America’s national parks look serene on the surface, but hidden dangers lurk among steep cliffs, unpredictable wildlife, and extreme weather conditions. Each year, millions of visitors flock to these scenic destinations—some established as early as the late 1800s—hoping to explore their natural wonders.
Yet unfamiliar terrain, sudden storms, and a wide range of outdoor activities often increase the risk of injury or even death. Whether it’s blazing desert heat or snowy mountain passes, nature can turn against the unprepared in the blink of an eye. In this list, we’ll reveal The 20 Most Dangerous National Parks in The US and explore why caution is a must for every intrepid traveler.
1. Grand Canyon National Park
Established in 1919 in northern Arizona, this iconic canyon may be visually breathtaking, but it’s notorious for steep drop-offs and scorching summer temperatures. Over the decades, sudden weather changes have led to dehydration and heat exhaustion for hikers. The mighty Colorado River has also claimed lives through unpredictable rapids, reminding visitors to be extra cautious on rafting trips. With millions of tourists visiting each year, overcrowded viewpoints can create additional hazards. Always check park advisories and carry sufficient water before venturing into the canyon’s depths.
2. Yosemite National Park
Yosemite, founded in 1890 in California’s Sierra Nevada mountains, boasts towering granite cliffs and cascading waterfalls. Despite its beauty, the park sees numerous accidents due to slippery rocks near falls and rock climbing mishaps. Harsh winters bring treacherous ice conditions, while wildlife encounters with bears and mountain lions can be startling. Its popularity means hiking trails can become dangerously crowded, especially around Half Dome. Always follow local regulations and watch your step around the park’s towering waterfalls.
3. Great Smoky Mountains National Park
Straddling the border of Tennessee and North Carolina since 1934, Great Smoky Mountains National Park is home to rugged backcountry trails that can be perilous for unprepared hikers. Dense fog and rapidly shifting weather conditions often disorient visitors. Black bear sightings are a common thrill, but they also demand caution and proper food storage practices. Flash floods in certain areas have caught many by surprise over the decades. Ensure you’re geared for sudden weather changes and keep a safe distance from wildlife.
4. Sequoia National Park
Established in 1890 and nestled in California’s southern Sierra Nevada mountains, Sequoia National Park is famous for towering giant sequoia trees. However, steep trails and extreme elevation changes can lead to altitude sickness, especially at higher elevations like Mount Whitney. Unpredictable snowfall and ice add to the park’s dangers, making winter travel risky. Meanwhile, wildlife like black bears and cougars roam the forests, demanding caution during camping trips. Always pace yourself when hiking and pay attention to park alerts.
5. Denali National Park
Located in interior Alaska, Denali National Park became a designated park in 1917 and is dominated by the towering Denali peak. Harsh subarctic climates, avalanche-prone slopes, and remote wilderness areas make for a risky adventure. Wildlife encounters with moose, grizzly bears, and wolves often catch visitors off-guard, especially during unpredictable weather shifts. Limited accessibility also complicates rescue efforts when accidents happen. If you visit, plan thoroughly, pack proper gear, and be prepared for sudden snowstorms even in summer.
6. Glacier National Park
Nestled in northwestern Montana since 1910, Glacier National Park lures travelers with stunning alpine views and crystal-clear lakes. Yet the park’s narrow, winding roads, including the famous Going-to-the-Sun Road, can be hazardous due to ice and swift mountain weather changes. Slippery trails, hidden crevasses, and encounters with grizzly bears in the backcountry demand constant vigilance. Lake conditions can shift rapidly, posing a threat to inexperienced swimmers and boaters. Prior research and a cautious approach are essential for a safe trip.
7. Zion National Park
Utah’s first national park, designated in 1919, Zion offers rugged slot canyons and dramatic red rock formations. But these very canyons can flood in minutes during sudden rainstorms, creating deadly flash flood conditions. Steep trails like Angel’s Landing have claimed lives due to narrow ledges and intense drop-offs. High temperatures in the peak summer months can also lead to severe dehydration. A reliable weather forecast check and sturdy hiking footwear go a long way here.
8. Yellowstone National Park
Celebrated as the first national park in the world since 1872, Yellowstone in Wyoming, Montana, and Idaho has mesmerizing geothermal features that can be extremely dangerous. Boiling hot springs and geysers with fragile crusts have caused severe burns and tragic falls. Wildlife like bison and grizzly bears can turn aggressive if provoked, especially during mating or calving seasons. Sudden weather changes across its vast terrain also pose a threat to ill-prepared campers. Keeping a safe distance from animals and staying on marked trails are top safety tips.
9. Death Valley National Park
Established in 1994 across California and Nevada, Death Valley is infamous for its blistering heat, which can soar above 120°F (49°C). Car breakdowns on remote roads become life-threatening if travelers lack water and backup plans. The extreme dryness and unrelenting sun make heatstroke and dehydration very real dangers. Dust storms can reduce visibility to zero, complicating driving conditions. Plan visits during cooler seasons and carry ample water for a safer journey.
10. Mount Rainier National Park
Located in Washington State since 1899, Mount Rainier’s massive volcano is known for its unpredictable weather and glacier-covered slopes. Heavy snowfall can trigger avalanches, and sudden whiteouts make navigation nearly impossible. Crevasses on the glaciers pose lethal threats to climbers who venture off-trail. Even summer hikers can encounter severe storms and hypothermia in the higher elevations. Investing in a knowledgeable guide and respecting the mountain’s power are wise decisions here.
11. Hawaii Volcanoes National Park
Hawaii Volcanoes National Park, established in 1916 on the Big Island, is home to active volcanoes like Kīlauea. Lava flows, volcanic vents, and toxic gases can catch travelers unawares if they stray from designated viewing areas. The jagged, freshly cooled lava rock also presents treacherous footing, leading to sprains or worse. Vog (volcanic smog) can impact breathing for those with respiratory problems. Always heed eruption warnings and stay within official safety zones.
12. Everglades National Park
Designated in 1934 in southern Florida, Everglades National Park features an extensive wetland ecosystem filled with alligators, crocodiles, and venomous snakes. Warm, swampy conditions breed aggressive mosquitoes and biting insects that can carry diseases if left unchecked. Water-related hazards, including deep channels and strong currents, can be life-threatening for boaters and kayakers. Hurricanes periodically sweep through, adding yet another layer of risk. Proper insect repellent, navigation tools, and checking weather alerts are crucial for safe exploration.
13. Rocky Mountain National Park
Founded in 1915 in Colorado, Rocky Mountain National Park offers soaring peaks that exceed 14,000 feet in elevation. Sudden snowfalls and lightning storms are common, particularly in the summer months. Altitude sickness poses a serious threat for visitors who ascend too quickly. Wildlife, including elk and black bears, sometimes approach campgrounds, requiring heightened awareness. Gradual acclimatization and careful route planning help mitigate these high-altitude risks.
14. Big Bend National Park
Located in southwest Texas along the Rio Grande since 1944, Big Bend’s rugged desert and river environments create unique challenges. High daytime temperatures, especially from May to September, can overwhelm visitors who haven’t packed sufficient water or shelter. The park’s remote location also means medical help is far away if accidents occur while rafting or hiking. Trails can be poorly marked, and wildlife like rattlesnakes add another layer of danger. Always inform someone of your travel plans and carry a detailed map when exploring.
15. Channel Islands National Park
Officially designated in 1980 off the coast of Southern California, Channel Islands National Park might appear tranquil from afar, but turbulent waters and strong ocean currents surround these islands. Sudden changes in sea conditions pose risks for boaters, divers, and kayakers. Limited resources on the islands mean emergencies can quickly escalate without timely help. The rugged, undeveloped nature of the terrain also hides slippery rocks and steep coastal cliffs. Hiring an experienced guide and checking marine forecasts can save you from harrowing situations.
16. Olympic National Park
Designated in 1938 in Washington’s Olympic Peninsula, this park contains diverse ecosystems from rainforests to alpine peaks. Torrential rainfall often makes trails slick and muddy, increasing the likelihood of accidents. Fog and cloud cover in the mountains can reduce visibility, complicating navigation for hikers. Coastal areas along the Pacific can see violent storms, and sneaker waves pose hidden perils to beach walkers. Packing layered clothing and checking tide schedules are essential precautions here.
17. Bryce Canyon National Park
Established in 1928 in southern Utah, Bryce Canyon’s distinctive hoodoos and colorful limestone formations draw adventurous visitors worldwide. The elevation, which exceeds 8,000 feet at some viewpoints, can lead to altitude sickness and shortness of breath. Steep trails and sudden weather shifts, including thunderstorms, challenge even experienced hikers. Winter snow can create icy paths along the canyon rim, greatly increasing slip-and-fall accidents. Hydration, warm layers, and mindful foot placement go a long way in staying safe.
18. Canyonlands National Park
Situated in southeastern Utah since 1964, Canyonlands captivates explorers with its arid desert landscape and deep canyons carved by the Colorado River. Intense heat and lack of water sources make dehydration a serious threat. Off-road driving accidents are not uncommon, as 4×4 trails can be deceptive and unmarked. Rattlesnakes and scorpions also lurk amid the desert rocks, demanding vigilance. Bring extra water, a well-maintained vehicle, and a good map to avoid unexpected mishaps.
19. Joshua Tree National Park
Established in 1994 in southern California, Joshua Tree combines desert and rugged mountain terrain with a stark beauty that lures climbers and campers year-round. Triple-digit heat in the summer can lead to life-threatening dehydration, while winter nights can drop below freezing. Unpredictable weather, combined with limited cell service in many areas, complicates rescue efforts in emergencies. Climbing accidents are frequent due to rocky, unstable surfaces. A solid understanding of desert survival skills and proper gear can make the difference between a safe visit and a disastrous one.
20. Arches National Park
Located just outside Moab, Utah, and established in 1971, Arches features over 2,000 naturally formed sandstone arches. While the formations are magnificent, many trails involve steep ledges and exposed cliff edges. Intense sun and high temperatures in the warmer months can overwhelm hikers who venture without adequate water. The sandstone itself is also fragile, and venturing off-trail can lead to dangerous falls or collapses. Always keep to marked paths, follow park guidelines, and remain mindful of the extreme desert conditions.
