To prepare you for your trip, I will give you a little introduction to the alpine, which is the dominant ecosystem that you will find up at Niwot Ridge.
Alpine ecosystems, sometimes called "alpine tundra", are ecosystems found at high elevation, such as on the tops of tall mountains. These ecosystems experience extremely cold and windy winters and short cool summers which are also often quite windy. There is lots of ultraviolet radiation, and the air is thin. The landscape often consists of steep slopes with rocky, thin soils. All of these characteristics control the types of plants that can grow up in alpine areas. The plants that grow up there are usually very short -- growing very close to the ground. Down near the ground the wind doesn't blow as hard and the temperature is often a little warmer.
| Impressive Wind and Cold!! |
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| Up on Niwot Ridge, the wind speed that begins to lift a person off the ground if they try to remain on two feet, instead of lying on the ground, is about 118 miles per hour. So, at higher speeds, one either lays on the ground, or gets lifted off. It once took about four hours to travel just over one mile, from Saddle to D1 on Niwot Ridge, when the wind speed was averaging 90 MPH with gusts to 120 MPH once a minute. The coldest temperatures at Niwot Ridge are not really any colder than those found out on the eastern plains because cold air is heavier than warm air and settles to the lowest topographic points. The average minimums, however, are definitely colder on Niwot Ridge. About -40 C or F is a good general low minimum temperature for the Ridge, though it doesn't always get that cold. - Mark Losleben |
What's the weather like on the tundra, today? Click here (you will need to hit the "back" key to return to the fieldtrip.)
The weather at 11,600 ft (3525 m) elevation
All that grows in the highest meadows is "cushion plants", which don't stick up much above the ground at all. They have far more roots than they have leaves and flowers, and they grow so slowly that it often takes several years before they produce a flower. Look at the pictures of Arctic Sandwort on the plants page and you will see how little these plants are.
In meadows lower down you can find taller plants and willow shrubs, but these plants and shrubs are still much shorter than shrubs that you will see down here.
As you get lower down the mountain you will reach a krummholz region. This is the limit at which trees can grow, and the trees -- pines, spruce, and fir -- look nothing like the trees you have seen in the forests at lower elevations. They are wider than they are tall because they grow along the ground rather than upright. Some people call them "tree islands". They form a shape like a wedge, with a thinner point at the end facing towards where the wind comes sloping up to a taller end away from the wind. The wind wears down the pointed end and kills it, while the branches on the end that is sheltered from the wind get buried, put out roots, and grow new branches. Because the end facing the wind is dying back while the other end is growing forward, these trees actually crawl along the ground -- almost as though they are trying to crawl away from the wind. But even the end that is growing away from the wind doesn't get very tall, perhaps no taller than you are. The parts of the tree that grow too tall in the summer don't last through the winter, and this keeps the tree short. In the winter, snow will bury the bottom part of the tree. The parts that stick up above the snow get scoured by tiny pieces of ice blown by the strong winds. The ice acts like sandpaper and scrapes off the protective waxes on the branches and needles, and they lose all their moisture and die.
In the summer you will see some of the tallest flowers hiding at the ends of these tree islands farthest from the wind. You will also see taller trees hiding behind rocks. You can tell which way the wind blows from most often by the shapes of the tree islands and the places where the plants hide.
| Deep Snow!! |
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| The deepest snow depth measured in the Green Lakes Valley in 1997 and 1998 was 9.4 meters on the Arikaree Glacier, or a snow depth of 31 feet! - Mark Williams |
| The deepest snow ever measured in Green Lakes Valley is even deeper than that measured in 1997-1998 -- it was greater than 15.4 meters, over 50 feet! (that's as deep as the probe could measure!) - Tim Bardsley |
Much like the plants, alpine animals tend to hide from the wind. They hide in the rocks or underground, so it is hard to find them. One of the bigger animals, a marmot, sometimes hides underneath the Tundra lab. Little pikas hide in the rock piles near the D1 research station, and sometimes if you sit really quiet you can see one run from one rock to another. Usually you can hear is their little "squeaky-screams" as they talk to each other. Gophers leave tubes of dirt on the ground that are easy to see, but the gophers themselves rarely come out of their burrows. Elk will occasionally wander by, but not nearly as many as you might see in Rocky Mountain National Park. Look at the photos of animals on the field trip so you can identify these animals if you do see them.
| Ice Age Animals - Lions and Mammoths and Bears! | ||
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| Summer temperatures were about 10-11 degrees Celsius (18-20 degrees F) colder during the last Ice Age (glaciation), about 18,000-14,000 years ago. Winter temperatures were even colder: about 23 degrees C (41 degrees F) colder than they are today. - Scott Elias |
During the last Ice Age the following large animals wandered Colorado: Giant Pleistocene bison, two species of giant ground sloths, two species of camels, a llama, the giant short-faced bear, the dire wolf, the North American lion, the North American cheetah, the saber-toothed cat, and the Columbian mammoth. | During the last glaciation, the alpine tundra zone expanded about 300-500 m downslope, so the isolated patches of tundra we see today only on mountain tops were once a much larger, continuous zone of tundra that formed a sort of peninsula of tundra habitat along the crest of the Rockies from southern Wyoming to northern New Mexico. |