Thimbleberry Falls, is a good example of how most waterfalls in Southeast Alaska were formed.
Summary: A well developed trail accessible by persons with disabilities leads from the parking lot to Thimbleberry Lake. A much less developed trail continues around Thimbleberry Lake over a low pass to connect with Heart Lake Trail.
Seasons: All Difficulty: Moderately Easy Elevation Change: Slight/Moderate Route Finding: Easy to Moderate Trail Condition: Very Good to Poor Getting There: Drive out Sawmill Creek Boulevard from downtown three or four miles to a large turnout/parking lot on the left side of the road. (If you see Whale Park, you have gone too far.) The trailhead sign is quite visible along the edge of the parking lot closest to town.
Things to See Thimbleberry Falls is easily seen from the trail. Thimbleberry Lake has a boat or two that can be used on a first come first served basis (you may want to bring your own oars).
The Tongass National Forest is home to about 75,000 people who are dependent on the land for their livelihoods. Several Alaska Native tribes live throughout Southeast Alaska such as the Tlingit, Haida, and Tsimshian. 31 communities are located within the forest; the largest is Juneau, the state capital, with a population of 31,000. The forest is named for the Tongass group of the Tlingit people, who inhabited the southernmost areas of the Alaska panhandle near what is now Ketchikan. Along with British Columbia’s Great Bear Rainforest, Tongass is part of the "perhumid rainforest zone," and the forest is primarily made up of western red cedar, sitka spruce, and western hemlock. Tongass is Earth's largest remaining temperate rainforest. Unique and protected features seldom found anywhere else in North America inhabit the thousands of islands along the Alaska coast. Though its land area is huge, two thirds of the Tongass is not actually forest, but snow, ice, rock, and non-forest vegetation. The terrain underlying Tongass is divided between Karst (limestone rock, well-drained soil, and many caves), and Granite (poorly-drained soil).
Features
•Water defines the Tongass National Forest, from glacial melt to rain and snow, water impacts geology, soils, plant and animal tolerances and limits, migrations and seasonal fluctuations.
•16.9 million acres of public land and over 2000 islands and adjacent coastline from the southern tip of Prince of Wales Island 500 miles north to Hubbard Glacier north of Yakutat is within the Tongass National Forest. This is ninety percent of the southeastern panhandle of Alaska.
•Geologic and climatic variation within short distances of less than 1600 feet are so dramatic that vegetation and wildlife are distinctly zonated and adapted to rainfall and temperature extremes.
•Maritime and coastline adaptations are found in all life forms, including algae, fungi, lichens, mosses, bog and muskeg plants and animals, vast anadramous and non-anadramous fisheries, and high and low altitude dwelling animals and plants.
•Forests of hemlock, spruce, red and yellow cedar dominate the canopy of the temperate rainforest. In areas protected from salt laden winds, trees may live to be more than 500 years old. Approximately 83 percent of the old growth forests remain as they were 100 years ago, before commercial logging began.
•Half of the Tongass landforms include ice, water, muskeg (a form of acidic bog) and rock. 11,000 miles of shoreline within the Forest are formed from mountains reaching down slope to sea level, and glacial rivers of ice either perch above sea level or reach sea level as tidewater glaciers.
•Designated wilderness areas and two National Monuments comprise 35 percent of the Tongass National Forest, representing the highest percentage of any forest in the national forest system.
•Containing the largest concentration of caves and karst (calcium carbonate dominated geology) landscapes in Alaska, the Tongass examples are truly world class. These complex ecosystems are of geological, paleohydrological, paleontological, and archaeological significance, and add significantly to our understanding of natural and cultural resources of Prince of Wales Island.
•Habitats that support large populations of coastal grizzly bears, Alexander Archipelago wolves, mountain goats, and streams and waters that support five species of salmon occur on the Tongass National Forest.
•The Tongass is the home for many cultures and many peoples, from Alaska Native villages of Tlingit and Haida tribes and the Annette Island Reservation of Tshimshian tribes, to Euroamerican descendants of gold seekers, loggers, or commercial fishing. These multicultural communities continue today. Embedded in the Tongass National Forest, with the added dimension of ecotourism, and with statehood, politics added to the mix of rural economies.
A waterfall is usually a geological formation resulting from water, often in the form of a stream, flowing over an erosion-resistant rock formation that forms a sudden break in elevation or nick point.
Some waterfalls form in mountain environments where the erosive water force is high and stream courses may be subject to sudden and catastrophic change. In such cases, the waterfall may not be the end product of many years of water action over a region, but rather the result of relatively sudden geological processes such as landslides, faults or volcanic action.
Typically, a river flows over a large step in the rocks which may have been formed by a fault line. Over a period of years, the edges of this shelf will gradually break away and the waterfall will steadily retreat upstream, creating a gorge of recession. Often, the rock stratum just below the more resistant shelf will be of a softer type, meaning undercutting, due to splash back, will occur here to form a shallow cave-like formation known as a rock shelter or plunge pool under and behind the waterfall. Eventually, the outcropping, more resistant cap rock will collapse under pressure to add blocks of rock to the base of the waterfall. These blocks of rock are then broken down into smaller boulders by attrition as they collide with each other, and they also erode the base of the waterfall by abrasion, creating a deep plunge pool.
Streams become wider shallow just above waterfalls due to flowing over the rock shelf, and there is usually a deep pool just below the waterfall because of the kinetic energy of the water hitting the bottom.
Waterfalls can occur along the edge of glacial trough, whereby a stream or river flowing into a glacier continues to flow into a valley after the glacier has receded or melted. The large waterfalls in Yosemite Valley are examples of this phenomenon. The rivers are flowing from hanging valleys.
Types of Waterfalls...
Block: Water descends from a relatively wide stream or river.
Cascade: Water descends a series of rock steps.
Cataract: A large waterfall.
Fan: Water spreads horizontally as it descends while remaining in contact with bedrock.
Horsetail: Descending water maintains some contact with bedrock.
Plunge: Water descends vertically, losing contact with the bedrock surface.
Punchbowl: Water descends in a constricted form, and then spreads out in a wider pool.
Segmented: Distinctly separate flows of water form as it descends.
Tiered: Water drops in a series of distinct steps or falls.
Multi-Step: A series of waterfalls one after another of roughly the same size each with its own sunken plunge pool.
To get credit for this cache e-mail chiefsfan19 the answer to the following questions:
1) Post a picture of your party at ground zero near the falls.(optional)
2) Approximately how high are the falls?
3) Approximately how wide are the falls?
4) What type of Waterfall?
5) What body of water feeds the falls?
6) What man made object is just past the bridge?
Source: http://sitkatrailworks.org/index.php/trail-information/8-trails/17
Source: http://en.wikipedia.org/wiki/Tongass_National_Forest
Source: http://en.wikipedia.org/wiki/Waterfall