Yellowstone - nexus of beauty and danger

By Pramod De Silva

Yellowstone. The very name conjures up images of geysers, thermal springs, bison, majestic waterfalls, rivers, mountains and vast scenic landscapes. But there is another word associated with Yellowstone that is not so reassuring: Volcano. Yes, Yellowstone National Park, the oldest declared national park in the world (1872), sits atop one of the world’s largest super-volcanoes that can potentially cause enormous damage over much of the United States.

In fact, Yellowstone was struck last month by a magnitude 4.8 earthquake, the biggest recorded there since February 1980, but no damage or injuries were immediately reported. The tremor, a relatively light event by seismic standards, struck the Northwest corner of the park. The quake occurred near the centre of an area of ground uplift that geologists have been tracking for several months, About 1,000 to 3,000 earthquakes strike Yellowstone each year, according to the Yellowstone Volcano Observatory, a research partnership of the Park, the University of Utah and the U.S. Geological Survey.

Biggest volcanoes

The words volcano and earthquake were very much on my mind as I toured Yellowstone recently with my wife as the guide constantly reminded us that we were walking atop one of the world’s biggest volcanoes. It felt as if we had stepped onto another planet - the landscape around you is so out of this world, literally. Not surprisingly, scientists hoping to see life on alien planets study micro-organisms that thrive in Yellowstone’s hot springs.

You can tour Yellowstone for a lifetime and still learn new things every day since the national park spans 3,472 square miles (8,992 square km) of Wyoming, Montana and Idaho. It draws about three million visitors each year from all over the world to its well known geysers and wildlife attractions, including bison. The ancient super-volcano, or caldera, that lies beneath the surface of the park was discovered by scientists in recent years to be 2.5 times larger than previously thought, measured at 50 Km wide.

The good news is there was no indication that the recent seismic activity signalled an impending eruption of the Yellowstone Caldera. The bad news is that it might happen one day, may be not in our lifetimes.

With reports of bison fleeing the area after the most recent earthquake, some had predicted a massive eruption, but scientists dismissed the idea. In any case, when in Yellowstone, do stick to the park officials’ advice not to veer away from the designated paths and trails as the ground is unstable.

During the extensive tour of Yellowstone, I learned that catastrophic eruptions of the super-volcano are unlikely for tens of thousands of years, though less extreme lava releases could occur within thousands of years. According to the park’s naturalists, the super-volcano’s most cataclysmic eruption occurred nearly two million years ago, covering half of North America with ash. The eruption probably killed animals living as far away as modern-day Nebraska. If such an event were to occur today, one can imagine the scale of loss of life and destruction.

Stunningly beautiful

But that does not negate the fact that Yellowstone is stunningly beautiful in all seasons. We toured the park at the tail end of summer, but the park takes a life of its own even in the depths of winter. The park has a number of outstanding geothermal features, but the most well known is the geyser known as “Old Faithful” which alludes to the fact that it shoots water into the air at regular intervals. When you enter Yellowstone, just check the visitor centre bulletin board for the next ‘eruption’. Generally, you do not have to wait for more than 40 minutes. While Old Faithful is the most spectacular geyser, there are around 500 less well known geysers throughout the park.

But how are they generated? Heat from a vast chamber of molten rock beneath the caldera fuels the park’s famous geothermal features, including Old Faithful Geyser. The other most famous feature in Yellowstone is the Grand Prismatic Spring, which is a riot of colour that dazzles the eyes. At 250-by-300 feet and up to 160 feet deep, the Grand Prismatic Spring is the largest hot spring in the USA. Its brilliant colours are the result of pigmented bacteria living on its perimeter. The hues change and become more or less vibrant depending on the kinds of bacteria thriving at any given time.

The heat of the spring - it’s 72 degrees Celsius at the center - causes steam to waft and swirl, adding to the alien look of the place. Scientists are studying the bacteria in the hope of gaining of an understanding whether other planets could harbour extreme forms of life that can thrive in otherwise toxic environments. Again, there are a few other such hot springs dotted throughout Yellowstone, though none match the Grand Spring for sheer splendour.

Unmissable feature

Waterfalls are another unmissable feature at Yellowstone. There are more than 45 named waterfalls and a few more unnamed ones. The highest plunge type waterfall in the park is the lower Falls at 308 feet (94 m). The highest horsetail type is Silver Cord Cascade at 1,200 feet (370 m). The latter is a huge spectacle, admired from some distance away. The waterfalls are associated with a number of rivers that add beauty to the park.

If you go on safari in Sri Lanka, you do not want to miss seeing an elephant. The Yellowstone equivalent is the bison, which is now thriving in several parts of the US. In fact, our tour bus had to go rather slowly to give way for a herd of bison crossing the road. It is a traffic-stopping scene, with these proud animals slumbering along the highway that goes by Yellowstone. There are more than 3,700 bison in Yellowstone, so you will not miss them.

Among the other animals that call Yellowstone home are bighorn sheep, elk, wolves, bears (notoriously difficult to see), moose and pronghorn. Indeed, Yellowstone is a geological as well as wildlife marvel that you cannot afford to miss if you visit the USA. As the plaque at one of the entrances says, Yellowstone is “for the benefit and enjoyment of the people”.

A thermal spring	A majestic waterfall