The Snake River is a major river of the greater Pacific Northwest region in the United States. At 1,078 miles (1,735 km) long, it is the largest tributary of the Columbia River, in turn, the largest North American river that empties into the Pacific Ocean. The Snake River rises in western Wyoming, then flows through the Snake River Plain of southern Idaho, the rugged Hells Canyon on the Oregon–Idaho border and the rolling Palouse Hills of Washington, emptying into the Columbia River at the Tri-Cities in the Columbia Basin of Eastern Washington.
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.
Landforms are categorized by characteristic physical attributes such as their creating process, shape, elevation, slope, orientation, rock exposure, and soil type.
The Wasatch Range or Wasatch Mountains is a mountain range in the western United States that runs about 160 miles (260 km) from the Utah-Idaho border south to central Utah. It is the western edge of the greater Rocky Mountains, and the eastern edge of the Great Basin region. The northern extension of the Wasatch Range, the Bear River Mountains, extends just into Idaho, constituting all of the Wasatch Range in that state.
The Yampa River flows 250 miles (400 km) through northwestern Colorado, United States. Rising in the Rocky Mountains, it is a tributary of the Green River and a major part of the Colorado River system. The Yampa is one of the few free-flowing rivers in the western United States, with only a few small dams and diversions.
The Dolores River is a tributary of the Colorado River, approximately 241 miles (388 km) long, in the U.S. states of Colorado and Utah. The river drains a rugged and arid region of the Colorado Plateau west of the San Juan Mountains. Its name derives from the Spanish El Rio de Nuestra Señora de Dolores, River of Our Lady of Sorrows. The river was explored and possibly named by Juan Maria Antonio Rivera during a 1765 expedition from Santa Fe.
The geology of the Grand Canyon area includes one of the most complete and studied sequences of rock on Earth. The nearly 40 major sedimentary rock layers exposed in the Grand Canyon and in the Grand Canyon National Park area range in age from about 200 million to nearly 2 billion years old. Most were deposited in warm, shallow seas and near ancient, long-gone sea shores in western North America. Both marine and terrestrial sediments are represented, including lithified sand dunes from an extinct desert. There are at least 14 known unconformities in the geologic record found in the Grand Canyon.
The exposed geology of the Bryce Canyon area in Utah shows a record of deposition that covers the last part of the Cretaceous Period and the first half of the Cenozoic era in that part of North America. The ancient depositional environment of the region around what is now Bryce Canyon National Park varied from the warm shallow sea in which the Dakota Sandstone and the Tropic Shale were deposited to the cool streams and lakes that contributed sediment to the colorful Claron Formation that dominates the park's amphitheaters.
The Santa Ana River is the largest river entirely within Southern California in the United States. It rises in the San Bernardino Mountains and flows for most of its length through San Bernardino and Riverside counties, before cutting through the northern Santa Ana Mountains via Santa Ana Canyon and flowing southwest through urban Orange County to drain into the Pacific Ocean. The Santa Ana River is 96 miles (154 km) long, and its drainage basin is 2,650 square miles (6,900 km2) in size.
The San Gabriel River is a mostly urban waterway flowing 58 miles (93 km) southward through Los Angeles and Orange Counties, California in the United States. It is the central of three major rivers draining the Greater Los Angeles Area, the others being the Los Angeles River and Santa Ana River. The river's watershed stretches from the rugged San Gabriel Mountains to the heavily developed San Gabriel Valley and a significant part of the Los Angeles coastal plain, emptying into the Pacific Ocean between the cities of Long Beach and Seal Beach.
The exposed geology of the Capitol Reef area presents a record of mostly Mesozoic-aged sedimentation in an area of North America in and around Capitol Reef National Park, on the Colorado Plateau in southeastern Utah.
The term freshet is most commonly used to describe a snowmelt, an annual high water event on rivers resulting from snow and river ice melting. A spring freshet can sometimes last several weeks on large river systems, resulting in significant inundation of flood plains as the snowpack melts in the river's watershed. Freshets can occur with differing strength and duration depending upon the depth of the snowpack and the local average rates of warming temperatures. Deeper snowpacks which melt quickly can result in more severe flooding. Late spring melts allow for faster flooding; this is because the relatively longer days and higher solar angle allow for average melting temperatures to be reached quickly, causing snow to melt rapidly. Snowpacks at higher altitudes and in mountainous areas remain cold and tend to melt over a longer period of time and thus do not contribute to major flooding. Serious flooding from southern freshets are more often related to rain storms of large tropical weather systems rolling in from the South Atlantic or Gulf of Mexico, to add their powerful heating capacity to lesser snow packs. Tropically induced rainfall influenced quick melts can also affect snow cover to latitudes as far north as southern Canada, so long as the generally colder air mass is not blocking northward movement of low pressure systems.
U-shaped valleys, also called trough valleys or glacial troughs, are formed by the process of glaciation. They are characteristic of mountain glaciation in particular. They have a characteristic U shape in cross-section, with steep, straight sides and a flat or rounded bottom. Glaciated valleys are formed when a glacier travels across and down a slope, carving the valley by the action of scouring. When the ice recedes or thaws, the valley remains, often littered with small boulders that were transported within the ice, called glacial till or glacial erratic.
The Geology of Pennsylvania consists of six distinct physiographic provinces, three of which are subdivided into different sections. Each province has its own economic advantages and geologic hazards and plays an important role in shaping everyday life in the state. From the southeast corner to the northwest corner of the state, the include: the Atlantic Plain Province province, the Piedmont Province, the New England Province, the Ridge and Valley Province, the Appalachain Province, and the Central Lowlands Province.
San Juan Creek, also called the San Juan River, is a 29-mile (47 km) long stream in Orange and Riverside Counties, draining a watershed of 133.9 square miles (347 km2). Its mainstem begins in the southern Santa Ana Mountains in the Cleveland National Forest. It winds west and south through San Juan Canyon, and is joined by Arroyo Trabuco as it passes through San Juan Capistrano. It flows into the Pacific Ocean at Doheny State Beach. San Juan Canyon provides a major part of the route for California State Route 74.
In geography, a defile is a narrow pass or gorge between mountains or hills. The term originates from a military description of a route through which troops can march only in a narrow column or with a narrow front. On emerging from a defile into open country, soldiers are said to "debouch".
A river is a natural flowing watercourse, usually a freshwater stream, flowing on the surface or inside caves towards another waterbody at a lower elevation, such as an ocean, sea, bay, lake, wetland, or another river. In some cases, a river flows into the ground or becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to by names such as creek, brook, and rivulet. There are no official definitions for the generic term river as applied to geographic features, although in some countries or communities, a stream is defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in some parts of the United States, "burn" in Scotland and Northeast England, and "beck" in Northern England. Sometimes a river is defined as being larger than a creek, but not always; the language is vague.
The Trout Creek Mountains are a remote, semi-arid Great Basin mountain range mostly in southeastern Oregon and partially in northern Nevada in the United States. The range's highest point is Orevada View Benchmark, 8,506 feet (2,593 m) above sea level, in Nevada. Disaster Peak, elevation 7,781 feet (2,372 m), is another prominent summit in the Nevada portion of the mountains.
The Colorado River is a major river of the western United States and northwest Mexico in North America. Its headwaters are in the Rocky Mountains where La Poudre Pass Lake is its source. Located in north central Colorado it flows southwest through the Colorado Plateau country of western Colorado, southeastern Utah and northwestern Arizona where it flows through the Grand Canyon. It turns south near Las Vegas, Nevada, forming the Arizona–Nevada border in Lake Mead and the Arizona–California border a few miles below Davis Dam between Laughlin, Nevada and Needles, California before entering Mexico in the Colorado Desert. Most of its waters are diverted into the Imperial Valley of Southern California. In Mexico its course forms the boundary between Sonora and Baja California before entering the Gulf of California. This article describes most of the major features along the river.
The gaps of the Allegheny, meaning gaps in the Allegheny Ridge in west-central Pennsylvania, is a series of escarpment eroding water gaps along the saddle between two higher barrier ridge-lines in the eastern face atop the Allegheny Ridge or Allegheny Front escarpment. The front extends south through Western Maryland and forms much of the border between Virginia and West Virginia, in part explaining the difference in cultures between those two post-Civil War states. While not totally impenetrable to daring and energetic travelers on foot, passing the front outside of the water gaps with even sure footed mules was nearly impossible without navigating terrain where climbing was necessary on slopes even burros would find extremely difficult.
