Green Dragon Spring at Norris Geyser

A "hot spring" is a place where warm or hot groundwater issues from the ground on a regular basis for at least a predictable part of the year, and is significantly above the ambient ground temperature (which is usually around 55~57°F or 13~14°C in the eastern United States). The water is heated by geothermal heat, or heat generated from the interior of the Earth. This occurs in various "hot spots", where magma or other mantle material is close to the surface. If the water becomes so heated that it builds steam pressure and erupts in a jet above the surface of the Earth, it is called a geyser; if the water only reaches the surface in the form of steam, it is called a fumarole; and if the water is mixed with mud and clay, it is called a mud pot.

Warm springs are sometimes the result of hot and cold springs mixing but may also occur outside of geothermal areas, such as Warm Springs, Georgia (frequented for its therapeutic effects by polio-stricken U.S. President Franklin D. Roosevelt, who built the Little White House there). Because heated water can hold more dissolved solids, warm and especially hot springs also often have a very high mineral content, containing everything from simple calcium to lithium, and even radium. Because of both the folklore and the proven medical value some of these springs have, they are often popular tourist destinations, and locations for rehabilitation clinics for those with disabilities. [1] (http://www.rooseveltrehab.org) [2] (http://www.warmsprings.org)

The countries most famous for hot springs are Iceland and New Zealand. The onsen plays a notable role in Japanese culture.

North American hot springs

Throughout western North America (including Alaska) there are thousands of hot springs, many of which were created between 20 and 45 million years ago as a result of violent volcanic activity. They range in size from the tiniest seeps to near geysers; from seeps like Fales Hot Ditch north of Bridgeport, California, to subterranean lakes such as the one below Tonopah, Arizona, which provides natural mineral waters to the seven or more hot spring spas that once operated in Tonopah. The ruins of two such spas are still visible.

Native Americans and hot springs

In Tonopah, Arizona, it is probable that water flowed forth from the ground by itself for a few millennia. This led Native Americans to name the area Tonopah, meaning "Hot Water Under The Bush". Native Americans revered the hot springs as a sacred healing place. Though there are no Indian ruins in the immediate vicinity of the hot springs, the presence of grain grinding mortar holes, pottery shards, and other artifacts close by to the west are a clear indication that nomadic hunter-gatherers frequented the area for many years. Every major hot spring in North America, as well as those in South America, has some record of use by Native Americans, some for over 10,000 years.

Additionally, hundreds of very high quality arrowheads have been found at or near existing springs in Tonopah, indicating that Tonopah was a popular hunting ground. This abundance of artifacts is indicative of the importance of the springs to prehistoric peoples.

Native Americans always used these natural shrines in a state of complete nudity. If opposing tribes, even those at war, arrived at the same spring, all conflict ceased because they believed they were walking on sacred ground. Conversations were in hushed tones or, more often, didn't take place at all.

At least five United States national parks feature hot springs:

• Big Bend National Park in Texas [3] (http://www.nps.gov/bibe)
• Death Valley National Park in California [4] (http://www.nps.gov/deva)
• Hot Springs National Park in Arkansas [5] (http://www.nps.gov/hosp)
• Lassen Volcanic National Park in California [6] (http://www.nps.gov/lavo)
• Yellowstone National Park in Wyoming (and Idaho/Montana) [7] (http://www.nps.gov/yell)

Other hot or warm springs are located in:

• Glenwood Springs, Colorado
• Saratoga, Wyoming
• Tonopah, Arizona

Canada also has several hot springs located in Western Canada and list alphabetically as follows:

• Ainsworth: Cody Caves
• Province of Alberta: Banff Upper Hot Springs
• Gibson Marine Provincial Park: Ahousat Hot Springs
• Harrison Hot Springs, near Vancouver
• Invermere: Fairmont Hot Springs
• Maquinna Provincial Park: Hot Springs Cove
• Village of Nakusp: Coyote Springs, Halcyon Hot Springs, Halfway River, Nakusp Hot Springs, Octopus Creek, St. Leon, Upper Halfway River and Wilson Lake
• Pemberton: Meagre Creek Hot Springs, Sloquet Creek Hot Springs and Skookumchuck Hot Springs
• The Queen Charlotte Islands: Hot Springs Island
• Radium: Radium Hot Springs
• Revelstoke: Canyon Hot Springs
• Skookumchuck: Ram Creek Hot Springs
• Whiteswan Lake Provincial Park: Lussier Hot Springs
• Yukon Territory: Liard River Hot Springs

See also

• Spa town
• Bath

Further reading

• Marjorie Gersh-Young, Hot Springs and Hot Pools of the Southwest: Jayson Loam's Original Guide, Aqua Thermal Access, 2004. ISBN 1-890880-05-1.
• Marjorie Gersh-Young, Hot Springs & Hot Pools Of The Northwest, Aqua Thermal Access, 2003. ISBN 1-890880-04-3.
• G. J Woodsworth, Hot springs of Western Canada: a complete guide, West Vancouver: Gordon Soules Book Publishers. 1999. ISBN 0-919574-03-3.
• Clay Thompson, "Tonopah: It's Water Under The Bush", the Arizona Republic 1-12-03, p. B12.