Ever-Changing Yellowstone

Ever-Changing Yellowstone

Yellowstone is definitely not a sleepy world of natural wonders. The park truly feels alive when you see mud pots, steam vents, fumaroles, and paint pots -- all different aspects of the park's geyser basins, and all intriguing. Beyond the geyser activity, seasonal changes in wildlife and vegetation make Yellowstone fascinating to visit over and over again.

Though Old Faithful continues to spew routinely, even it has changed in recent years because of various factors. The geyser now erupts about every 94 minutes (up from 78 minutes in 1990), and it may look different each time. Monitoring shows that Old Faithful almost always spews forth the same amount of water at each eruption, but how it does so varies. Sometimes it shoots higher and faster, whereas other times it lasts longer but doesn't reach so high in the sky.

Other geyser basin features aren't so reliable. The force and nature of the various geysers depend on several factors, including the complex underground geology at Yellowstone. Rangers say the greatest threats to the geyser basin activity are earthquakes (which occur regularly in the region, though they are usually very small tremors) and the impact caused by people. In past years, for example, people threw hundreds of coins into the bright blue Morning Glory Pool. The coins eventually clogged the pool's water vents, causing it to change color to a sickly green. Though it has been cleaned and people are warned not to throw anything into it, the Morning Glory Pool has never regained its pristine color.

Besides of its unique geology, Yellowstone has many other faces. There are petrified forests and fossil remains of both plants and animals. The ongoing ecological development of the region draws widespread interest. The reintroduction of wolves to the ecosystem and efforts to control the movement of bison -- to keep them from wandering out of the park during the winter months in search of food -- are just two examples of issues that divide opinions on the management of Yellowstone.

Bison leave the park in winter -- mainly through the North and West entrances -- in part because of overpopulation and the need to find adequate feed. Their movements are sometimes made easier by the winter grooming of Yellowstone roads for use by over-snow vehicles.

Wolves were brought back to Yellowstone in 1995. They acclimated so well that they quickly formed several packs, some of which have ventured outside the park's boundaries. (Wolves from Yellowstone's packs have been spotted as far south as northern Utah and Colorado.) Their presence has had a lasting effect on wildlife populations. The wolves feed on both elk and buffalo, and researchers have noted a significant decline in elk calf survival throughout the region as a result of wolf predation. Park rangers have also reported a significant decline in Yellowstone's coyote population. Since the wolves are bigger and stronger than coyotes, they kill coyotes or force them to find a new range.

When massive wildfires tore through Yellowstone in 1988, some believed it would take generations for the park to recover. Already, the park has begun to renew itself. Certainly, when you visit Yellowstone now you will see reminders of fires from 1988 and more recent fires in 2001 and 2002, but you will also see the new growth. Lodgepole-pine forests need fire to release their seeds, and once seeds get a start, trees grow quickly. The new growth provides excellent cover for animals, making it harder for visitors to see wildlife such as elk, deer, and bears.