Alpine Visitor Center Cirque EarthCache
Alpine Visitor Center Cirque
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Rocky Mountain National Park is located west of Estes Park and north and east of Grand Lake. This is a fee area of the National Park Service, and costs $30 per vehicle. This fee is covered in the Rocky Mountain National Park Annual Pass, the Rocky Mountain National Park/Arapaho National Recreation Area Annual Pass, and the America the Beautiful Pass. Please see the following website (visit link) for the entire fee schedule. The park is open 24 hours a day, 365 days a year. Road and Trail Conditions and Closures can be found at: (visit link) Recorded information for the condition of Trail Ridge Road can be found by calling (970) 586-1222. Please remember that all geologic features within the borders of Rocky Mountain National Park are protected by law, as are all natural and historic features. Please do not disturb, damage, or remove any rocks, plants, or animals.
The Alpine Visitor Center, at 11,796’, is the highest visitor center in the National Park System. It is located on the northwest rim of the cirque which forms the headwaters of the Fall River. This cirque has seen many glaciers during several periods of glaciation during the past two million years.
Most cirques in Rocky Mountain National Park are on the north, northeast, or east sides of their respective ridges. This is due to the prevailing winds which helped to form the glaciers. Winds from primarily the southwest blew snow up and over the ridges, where it was deposited on the shaded northeast face. Over time, the weight of the accumulated snow and ice would compress, and cause the ice to move downhill.
The Fall River Glacier began at this cirque and headed downhill. Along the way, sediments were picked up in the form of soils, gravels, and boulders. Striations can be found in the rocks along Fall River Road where ice scoured the underlying rock with some of these sediments, causing scratches which can still be seen today. The Fall River Glacier acted like a huge U-shaped bulldozer, deepening and widening the narrow V-shaped ancient Fall River Valley and forming the distinctive steep-walled sides.
Fall River Glacier traveled down the valley about 8 miles to Horseshoe Park. Here, lateral moraines can be seen on the north and south sides of the park which consist of the sediments which were scooped up and carried along on the outer edges of the glacier. A terminal moraine is at the eastern end of Horseshoe Park near the furthest extent of the glacier. A large load of till was dropped at this location before the glacier began to recede.
Today, there is no longer a glacier associated with this cirque, but you are likely to see snow lasting well into the summer. As you might expect, the snow lasts longest on the southwest side, which is where the deeper snow drifts lie, and where there is less direct sunlight.
To receive credit for this EarthCache, send me an email with the answers to the following questions:
1.) Which direction does this cirque face?
2.) Estimate the width of the cirque at this location.
Please consider posting photos of yourself, or the local geology, when you log this EarthCache. Photos can be an additional rewarding part of your journey, but posting them is not a requirement for logging this EarthCache, and is strictly optional.
The above information was compiled from the following sources:
2004. Rocky Mountain National Park. In Harris, A.G. et al., editors. Geology of National Parks, Sixth Ed. P. 337-356. Dubuque, Iowa: Kendall/Hunt Publishing Company.
Cole, J.C., and Braddock, W.A. 2009. Geologic map of the Estes Park 30’ x 60’ quadrangle, north-central Colorado: U.S. Geological Survey Scientific Investigations Map 3039, 1 sheet, scale 1:100,000, 1 pamphlet, 56 p.
KellererLynn, K. 2004. Rocky Mountain National Park. Geologic Resource Evaluation Report. NPS D307, September 2004. Online at: (visit link)
Raup, O.P. 2005. Geology Along Trail Ridge Road. A Self-Guided Tour for Motorists. Estes Park, Colorado: Rocky Mountain Nature Association.
Rocky Mountain National Park. Online at: (visit link)
Informational signage at the site.
Rocky Mountain National Park was most helpful in the background discussion, aid in the choosing of sites, and review of this EarthCache. My thanks to the Park for allowing the placement of this EarthCache!
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