Spring into summer

We live in one of the most geothermal active locations in North America. The entire west coast is influenced by plate tectonics. As continental-sized pieces of crust slide against each other, they produce heat. This thermal activity can come to surface as hot springs. (above: Alpha Pond, Liard Hot Springs)

There are at least 70 major springs in northern British Columbia, Alaska, western Northwest Territories and the Yukon. They do not always have to be hot. No matter what the temperature is, a spring, according to the American Geological Institute is “a place where water flows naturally from rock or soil upon the land or into a body of surface water.”

The official definition of a “thermal” spring is one with a temperature that is five degrees above the mean annual air temperature for a location. For Whitehorse, the mean annual air temperature is about minus one degree Celsius, for Mayo it’s minus four, and for Old Crow, it’s minus 10. Above 32 degrees Celsius, a spring officially becomes a hot spring. Liard Hot Springs Alpha Pool is between 42 and 53 degrees Celsius, Takhini is around 45 and the Warm Springs south of Atlin can range from 10 to 30 degrees Celsius.
A lot of springs, especially the warmer ones, can carry a large amount of dissolved elements. If a spring carries more than 1000 milligrams per litre of total dissolved solids, it can be called a mineral spring. This is about twice the recommended maximum limits for drinking water.

When a spring is high in elements like sodium and magnesium and is frequented by wildlife, it may be known as a mineral lick. Wildlife studies in northern B.C. near Muncho Lake have shown that mineral licks are used by animals such as moose, elk, deer, goats and sheep. They frequent these locations mainly in the late spring/early summer before new nutrient-rich plant growth is readily available. Animals tended to stay one to two hours before moving on.

Studies in Denali National Park in Alaska showed that the most visited spring had the highest sodium content. Whether you are a moose or a human, sodium is an important electrolyte the body needs to function. As well as sodium and magnesium, springs can also be rich in calcium, iron, silica, sulphur and strontium. Natural strontium is harmless. It gets its bad name from a radioactive isotope produced only during nuclear explosions. Most springs are neutral to slightly alkaline in acidity.

You can get an idea of the chemistry of the water by the minerals that are deposited at surface. When the spring water contacts the air, it loses some of the carbon dioxide dissolved within it, just as a can of ginger ale loses its carbonation when you open it.
The loss of carbon dioxide from the water reduces the acidity and allows minerals to crystallize and precipitate (or drop out of) the water. The most common minerals are calcium carbonates (calcite, aragonite), sodium carbonates, calcium and magnesium sulphate (Epsom salts), and silica.

Calcite and aragonite are interesting minerals. They have the same chemical formula, CaCO3, but have different crystal shapes. It is like the difference between diamonds and graphite. Both are just different structures of carbon. Calcite is the softer of the two, but aragonite is a metastable mineral. Aragonite is formed at higher temperatures and pressures than calcite, but it will eventually change into calcite. This could take hundreds of millions of years, but the transformation does happen. The minerals accumulate and turn to rock known as travertine or tufa. If a silica mineral dominates, it is called sinter. The minerals can commonly accumulate as thin-walled rims that form pools. They can also cascade down a hill, forming terraces. The Hanging Gardens at Liard Hot Springs are a good example of this.

Hot springs often form along deep faults. These faults act as conduits for groundwater to be able to circulate down as far as two to three kilometres deep. Studies at hot springs in Japan show rocks at this depth were 200 to 300 degrees Celsius. The chemistry of Liard Hot Springs and Banff Hot Springs are very similar. Scientists believe that they both are related to deep thrust faults that formed the Rocky Mountains.

Hot springs create fantastic conditions for vibrant and exotic flora. In 1978, T.C. Reid, a graduate student at the University of Calgary, did a thesis on “The Vegetation and Environmental Patterns of Liard River Hot Springs.” He confirmed that thermally-influenced vegetation showed signs of earlier annual development. He also catalogued numerous species not normally found in the northern boreal forest. There are 14 types of orchids, exotic ferns, black snakeroot, stinging nettle and carnivorous aquatic plants like bladderwort. The ponds below the hot springs along the boardwalk are also home to Lake Chub minnows and the northwest boreal toad. The entire area is prime moose and bear habitat.

Hot springs are a natural draw for humans as well. Obsidian and lithic flakes used for hunting spears have been found near the Beta Pool at Liard Hot Springs. There are also indications of dug-out dwelling foundations. Citizens of the Na-Cho Nyäk Dun First Nation continue the long tradition of using the Nash Creek hot springs north of Mayo.

The first written European reference to Liard Hot Springs is in an 1830s journal of Robert Campbell. Word got around; George M. Dawson (of Dawson City fame) is known to have stopped at Liard at least twice on his journeys during the 1880s. With the coming of the Alaska Highway, the hot springs have been a mandatory stop for locals and tourists alike.
North of Liard Hot Springs along the Alaska Highway is the Portage-Brule Rapids. Here, along a two-kilometre stretch of the rapids, hot water discharges either directly into the Liard River, or forms pools along the shore depending on the river level.
When tungsten mining was active at Cantung, NWT, residents of the town enjoyed the 30 to 60 degree Celsius temperatures from the hot spring right nearby. The Warm Springs south of Atlin are the poster child of natural serenity. Chena Hot Springs in Alaska is only an hour north of Fairbanks. Ta’an Kwäch’än First Nation used the iron and strontium-rich hot springs just outside Whitehorse for centuries. Now known as the Takhini Hot Springs, they have remained in private ownership since the very early 1900s. 

If you are more adventurous and want to get away from the crowds, there are several remote springs.
The Coal River Springs Territorial Park was the first site in the Yukon to receive an Ecological Reserve designation. The springs are known for their extensive terrace development. The area is very remote and difficult to access. Contact Government of Yukon Parks for further information.
In northern British Columbia, Toad River Hot Springs Provincial Park is 12 kilometres northeast of the highway. It is accessible only by boat or by horseback. South of Iskut is the Iskut River Hot Springs Provincial Park. It is a six-kilometre hike west of the highway with no defined trail and you have to cross the river to get to the very hot water, which seeps out of the bank into the river. The Tahltan Nation has a long history of traditional use of this hot spring.

These are but a few of the dozens of springs in our area. No matter their size or location you can be sure any visit to a spring will be a unique and special experience.

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