A valley is an elongated low area often running between hills or mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams over a very long period. Some valleys are formed through erosion by glacial ice. These glaciers may remain present in valleys in high mountains or polar areas.
Lake Agassiz was a large proglacial lake that existed in central North America during late Pleistocene, fed by meltwater from the retreating Laurentide Ice Sheet at the end of the last glacial period. At its peak, the lake's area was larger than all of the modern Great Lakes combined.
The Wisconsin Glacial Episode, also called the Wisconsin glaciation, was the most recent glacial period of the North American ice sheet complex. This advance included the Cordilleran Ice Sheet, which nucleated in the northern North American Cordillera; the Innuitian ice sheet, which extended across the Canadian Arctic Archipelago; the Greenland ice sheet; and the massive Laurentide Ice Sheet, which covered the high latitudes of central and eastern North America. This advance was synchronous with global glaciation during the last glacial period, including the North American alpine glacier advance, known as the Pinedale glaciation. The Wisconsin glaciation extended from approximately 75,000 to 11,000 years ago, between the Sangamonian Stage and the current interglacial, the Holocene. The maximum ice extent occurred approximately 25,000–21,000 years ago during the last glacial maximum, also known as the Late Wisconsin in North America.
A tarn is a mountain lake, pond or pool, formed in a cirque excavated by a glacier. A moraine may form a natural dam below a tarn.
Glacial Lake Wisconsin was a prehistoric proglacial lake that existed from approximately 18,000 to 14,000 years ago, at the end of the last ice age, in the central part of present-day Wisconsin in the United States.
An arête is a narrow ridge of rock that separates two valleys. It is typically formed when two glaciers erode parallel U-shaped valleys. Arêtes can also form when two glacial cirques erode headwards towards one another, although frequently this results in a saddle-shaped pass, called a col. The edge is then sharpened by freeze-thaw weathering, and the slope on either side of the arête steepened through mass wasting events and the erosion of exposed, unstable rock. The word arête is actually French for "edge" or "ridge"; similar features in the Alps are often described with the German equivalent term Grat.
A pyramidal peak, sometimes called a glacial horn in extreme cases, is an angular, sharply pointed mountain peak which results from the cirque erosion due to multiple glaciers diverging from a central point. Pyramidal peaks are often examples of nunataks.
A cirque is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie and cwm. A cirque may also be a similarly shaped landform arising from fluvial erosion.
Lake Algonquin was a prehistoric proglacial lake that existed in east-central North America at the time of the last ice age. Parts of the former lake are now Lake Huron, Georgian Bay, Lake Superior, Lake Michigan, Lake Nipigon, and Lake Nipissing.
Interstate Park comprises two adjacent state parks on the Minnesota–Wisconsin border, both named Interstate State Park. They straddle the Dalles of the St. Croix River, a deep basalt gorge with glacial potholes and other rock formations. The Wisconsin park is 1,330 acres (538 ha) and the Minnesota park is 298 acres (121 ha). The towns of Taylors Falls, Minnesota and St. Croix Falls, Wisconsin are adjacent to the park. Interstate Park is within the Saint Croix National Scenic Riverway and the Ice Age National Scientific Reserve. The western terminus of the Ice Age National Scenic Trail is on the Wisconsin side. On the Minnesota side, two areas contain National Park Service rustic style buildings and structures that are listed on the National Register of Historic Places.
Lake Maumee was a proglacial lake and an ancestor of present-day Lake Erie. It formed about 17,500 calendar years, or 14,000 Radiocarbon Years Before Present (RCYBP) as the Huron-Erie Lobe of the Laurentide Ice Sheet retreated at the end of the Wisconsin glaciation. As water levels continued to rise the lake evolved into Lake Arkona and then Lake Whittlesey.
Snow Lake Peak is the fifth-highest named mountain of the Ruby Mountains and the seventh highest in Elko County, in Nevada, United States. It is the forty-second-highest mountain in the state. It rises from the head of Box Canyon, is part of the headwall of Thomas Canyon, and is a prominent part of the west wall of Lamoille Canyon above Lamoille and Dollar Lakes. The peak is located within the Ruby Mountains Wilderness of the Ruby Mountains Ranger District in the Humboldt-Toiyabe National Forest.
Pinkham Notch is a mountain pass in the White Mountains of north-central New Hampshire, United States. The notch is a result of extensive erosion by the Laurentide Ice Sheet during the Wisconsinian ice age. Pinkham Notch was eroded into a glacial U-shaped valley whose walls are formed by the Presidential, Wildcat, and Carter-Moriah ranges. Due to the volatility of the area's climate and rugged character of the terrain, a number of rare or endemic ecosystems have developed throughout the notch.
Huntington Ravine is a glacial cirque on Mount Washington in the White Mountains of New Hampshire. It is named for Joshua H. Huntington, the Principal Assistant to State Geologist Charles H. Hitchcock (1836–1919) for the Geological Survey of New Hampshire.
The proglacial lakes of Minnesota were lakes created in what is now the U.S. state of Minnesota in central North America in the waning years of the last glacial period. As the Laurentide Ice Sheet decayed at the end of the Wisconsin glaciation, lakes were created in depressions or behind moraines left by the glaciers. Evidence for these lakes is provided by low relief topography and glaciolacustrine sedimentary deposits. Not all contemporaneous, these glacial lakes drained after the retreat of the lobes of the ice sheets that blocked their outlets, or whose meltwaters fed them. There were a number of large lakes, one of which, Glacial Lake Agassiz, was the largest body of freshwater known to have existed on the North American continent; there were also dozens of smaller and more transitory lakes filled from glacial meltwater, which shrank or dried as the ice sheet retreated north.
Castle Lake is a glacial lake located in the Trinity Mountains, in Siskiyou County of northern California. It is west of Mount Shasta City and Mount Shasta peak.
Snoqualmie Lake is a lake in King County, Washington. It is an expansion of the Taylor River and is located a short distance downstream from Deer Lake. It is the largest of the three lakes along the upper reaches of the Taylor.
The Miller River is a river in King County, Washington. Named for 1890s prospector John Miller, it is a tributary of the Skykomish River, which it joins near the community of Miller River. The Miller River is about 3.5 miles (5.6 km) long from the confluence of its main tributaries, the East Fork and West Fork. Miller River Campground is located just downriver from the confluence.
Overdeepening is a characteristic of basins and valleys eroded by glaciers. An overdeepened valley profile is often eroded to depths which are hundreds of metres below the lowest continuous surface line along a valley or watercourse. This phenomenon is observed under modern day glaciers, in salt-water fjords and fresh-water lakes remaining after glaciers melt, as well as in tunnel valleys which are partially or totally filled with sediment. When the channel produced by a glacier is filled with debris, the subsurface geomorphic structure is found to be erosionally cut into bedrock and subsequently filled by sediments. These overdeepened cuts into bedrock structures can reach a depth of several hundred metres below the valley floor.
Lake Warren was a proglacial lake that formed in the Lake Erie basin around 12,700 years before present (YBP) when Lake Whittlesey dropped in elevation. Lake Warren is divided into three stages: Warren I 690 feet (210 m), Warren II 680 feet (210 m), and Warren III 675 feet (206 m), each defined by the relative elevation above sea level.
