Yellowstone National Park is a United States National Park and a UNESCO World Heritage Site. It was the world's first national park, set aside in 1872 to preserve the vast number of geysers, hot springs, and other thermal areas, as well as to protect the incredible wildlife and rugged beauty of the area. The park is principally contained within the northwest corner of Wyoming, but also extends into the states of Idaho and Montana.
» UnderstandYellowstone is the first and oldest national park in the world and covers 3,472 square miles (8,987 km²), mostly in the northwest corner of Wyoming. The park is famous for its various geysers, hot springs, and other geothermal features and is home to grizzly bears, wolves, and free-ranging herds of bison and elk.
» HistoryLong before any recorded human history in Yellowstone, a massive volcanic eruption spewed an immense volume of ash that covered all of the western U.S., much of the Midwest, northern Mexico and some areas of the eastern Pacific Coast. The eruption dwarfed that of Mt. St. Helens in 1980 and left a huge caldera. Yellowstone typically erupts every 600,000 to 900,000 years with the last event occurring 640,000 years ago. Its eruptions are among the largest known to have ever occurred on Earth, producing drastic climate change in the aftermath. Although it is commonly assumed that the park was named for the yellow rocks seen in the Grand Canyon of the Yellowstone, the park's name comes from the Yellowstone River that flows through it, which is in turn named after sandstone bluffs found farther down its course in eastern Montana.
On March 1,1872, Yellowstone became the first National Park reserve declared anywhere in the world, by President Ulysses S. Grant. In 1978 it was designated a World Heritage Site by UNESCO.
» LandscapeGeological characteristics form the foundation of an ecosystem. In Yellowstone, the interplay between volcanic, hydrothermal, and glacial processes and the distribution of flora and fauna are intricate and unique. The topography of the land from southern Idaho northeast to Yellowstone results from millions of years of hotspot influence. Some scientists believe the Yellowstone Plateau itself is a result of uplift due to hotspot volcanism.
» Flora and faunaThe park is the core of the Greater Yellowstone Ecosystem, one of the largest intact temperate zone ecosystems remaining on the planet. Black bears, grizzly bears, deer, elk, bison, bighorn sheep and wolves can all be found within the park borders.
» Geothermal FeaturesPrimary geothermal features include geysers, mud pots, hot springs and fumaroles, which exist because of the active volcano that Yellowstone sits on top of. Geothermal features are formed by superheated water heated by the volcano. The pressure is so intense that it gets released into the air as hundreds of gallons of steaming water, or, when the pressure is not as intense, hot springs or mud pots are formed. Various colors of the pool are due to different types of bacteria growing in different temperatures. A good way to learn about the geothermal features is through the Young Scientist Program. Please check with a Ranger at the Old Faithful Visitor Center.
» ClimateThe weather in Yellowstone National Park can change very rapidly from sunny and warm to cold and rainy, so it's important to bring along extra layers of clothing which can be used as needed.
▪ Summer: Daytime temperatures are often in the 70s (25°C) and occasionally in the 80s (30°C) in lower elevations. Nights are usually cool and temperatures may drop below freezing at higher elevations. Thunderstorms are common in the afternoons.
▪ Winter: Temperatures often range from zero to 20°F(-20°C to -5°C) throughout the day. Sub-zero temperatures over-night are common. The record low temperature is -66F (-54°C). Snowfall is highly variable. While the average is 150 inches per year, it is not uncommon for higher elevations to get twice that amount.
▪ Spring & Fall: Daytime temperatures range from the 30s to the 60s (0 to 20°C) with overnight lows in the teens to single digits (-5 to -20°C). Snow is common in the Spring and Fall with regular accumulations of 12" in a 24 hour period. At any time of year, be prepared for sudden changes. Unpredictability, more than anything else, characterizes Yellowstone’s weather. Always be equipped with a wide range of clothing options. Be sure to bring a warm jacket and rain gear even in the summer.