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Avalanches
An avalanche is a rapid flow of snow down a slope, such as a hill or mountain. Avalanches can be set off spontaneously, by such factors as increased precipitation or snowpack weakening, or by external means such as humans, animals, and earthquakes. Primarily composed of flowing snow and air, large avalanches have the capability to capture and move ice, rocks, and trees. Avalanches occur in two general forms, or combinations thereof: slab avalanches made of tightly packed snow, triggered by a collapse of an underlying weak snow layer, and loose snow avalanches made of looser snow. After being set off, avalanches usually accelerate rapidly and grow in mass and volume as they capture more snow. If an avalanche moves fast enough, some of the snow may mix with the air, forming a powder snow avalanche. Though they appear to share similarities, avalanches are distinct from slush flows, mudslides, rock slides, and serac collapses. They are also different from large scale movements ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avalanche On Everest
An avalanche is a rapid flow of snow down a Grade (slope), slope, such as a hill or mountain. Avalanches can be set off spontaneously, by such factors as increased precipitation or snowpack weakening, or by external means such as humans, animals, and earthquakes. Primarily composed of flowing snow and air, large avalanches have the capability to capture and move ice, rocks, and trees. Avalanches occur in two general forms, or combinations thereof: slab avalanches made of tightly packed snow, triggered by a collapse of an underlying weak snow layer, and loose snow avalanches made of looser snow. After being set off, avalanches usually accelerate rapidly and grow in mass and volume as they capture more snow. If an avalanche moves fast enough, some of the snow may mix with the air, forming a powder snow avalanche. Though they appear to share similarities, avalanches are distinct from slush flows, Mudflow, mudslides, Landslide#Debris landslide, rock slides, and serac collapses. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Avalanches By Death Toll ...
This is an incomplete list of notable avalanches. See also *Avalanche *List of natural disasters by death toll References External links {{DEFAULTSORT:List Of Avalanches * Avalanches in the United States Death in the United Kingdom Death in the United States Avalanches Avalanche An avalanche is a rapid flow of snow down a slope, such as a hill or mountain. Avalanches can be set off spontaneously, by such factors as increased precipitation or snowpack weakening, or by external means such as humans, animals, and earth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Powder Snow Avalanche
thumbnail, Example of powder snow avalanche A powder snow avalanche is a type of avalanche where snow grains are largely or completely suspended and moved by air in a state of fluid turbulence. They are particle-laden gravity currents and closely related to turbidity currents, pyroclastic flows from volcanoes and dust storms in the desert. The turbulence is typically generated by the forward motion of the current along the lower boundary of the domain, the motion being in turn driven by the action of gravity on the density difference between the particle-fluid mixture and the ambient fluid. The ambient fluid is generally of similar composition to (and miscible with) the interstitial fluid, and is water for turbidity currents and air for avalanches. These flows are non-conservative in that they may exchange particles at the lower boundary by deposition or suspension, and may exchange fluid with the ambient by entrainment or detrainment. Such flows dissipate when the turbulence can n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avalanche Control
Avalanche control or avalanche defense activities reduce the hazard avalanches pose to human life, activity, and property."Mitigation and Land Use - Avalanches" , Colorado Geological Survey Avalanche control begins with a risk assessment conducted by surveying for potential avalanche terrain by identifying geographic features such as vegetation patterns, drainages, and seasonal snow distribution that are indicative of avalanches. From the identified avalanche risks, the hazard is assessed by identifying threatened human geographic features such as roads, ski-hills, and buildings. Avalanche control programs address the avalanche hazard by formulating prevention and mitigation plans, which are then executed during the winter season. The prevention and mitigation plans combine extensive snow pack observation wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Hazard
A natural hazard is a natural phenomenon that might have a negative effect on humans and other animals, or the environment. Natural hazard events can be classified into two broad categories: geophysical and biological. An example of the distinction between a natural hazard and a disaster is that an earthquake is the hazard which caused the 1906 San Francisco earthquake disaster. Natural hazards can be provoked or affected by anthropogenic processes, e.g. land-use change, drainage and construction. There are 18 natural hazards included in the National Risk Index of FEMA: avalanche, coastal flooding, cold wave, drought, earthquake, hail, heat wave, hurricane (tropical cyclone), ice storm, landslide, lightning, riverine flooding, strong wind, tornado, tsunami, volcanic activity, wildfire, winter weather. In addition there are also tornados and dust storms. Several of these have a higher risk of occurring now due to the effects of climate change. Terminology Multi-hazard a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slush Flow
A slushflow is rapid mass movement of water and snow, and is categorized as a type of debris flow. Slushflows are caused when water reaches a critical concentration in the snowpack due to more water inflow than outflow. The high water concentration weakens the cohesion of the snow crystals and increases the weight of the snowpack. A slushflow is released when the component of the force of gravity parallel to the slope generates a hydraulic pressure gradient exceeding the tensile strength and basal friction of the snowpack. While frequently compared to an avalanche, they have some key differences. Slushflows are lower in frequency than avalanches, have higher water content, are more laminar in flow, and have lower velocity. They most commonly occur at higher latitudes in the winter during high precipitation and in the spring during high snowmelt. Because of their high water content, they can flow down gentle slopes of only a few degrees at low altitudes. They are a significant haza ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snow
Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout its life cycle, starting when, under suitable conditions, the ice crystals form in the atmosphere, increase to millimeter size, precipitate and accumulate on surfaces, then metamorphose in place, and ultimately melt, slide or sublimate away. Snowstorms organize and develop by feeding on sources of atmospheric moisture and cold air. Snowflakes nucleate around particles in the atmosphere by attracting supercooled water droplets, which freeze in hexagonal-shaped crystals. Snowflakes take on a variety of shapes, basic among these are platelets, needles, columns and rime. As snow accumulates into a snowpack, it may blow into drifts. Over time, accumulated snow metamorphoses, by sintering, sublimation and freeze-thaw. Where the climate is co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snowpack
Snowpack forms from layers of snow that accumulate in geographic regions and high elevations where the climate includes cold weather for extended periods during the year. Snowpacks are an important water resource that feed streams and rivers as they melt. Therefore, snowpacks are both the drinking water source for many communities and a potential source of flooding (in case of sudden melting). Snowpacks also contribute mass to glaciers in their accumulation zone. Assessing the formation and stability of snowpacks is important in the study and prediction of avalanches. Scientists study the physical properties of snow under different conditions and their evolution, and more specifically snow metamorphism, snow hydrology (that is, the contribution of snow melt to catchment hydrology), the evolution of snow cover with climate change and its effect on the ice–albedo feedback and hydrology, both on the ground and by using remote sensing. Snow is also studied in a more global context o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snowboarder Triggered Soft Slab Near Mount Baker
Snowboarding is a recreational and competitive activity that involves descending a snow-covered surface while standing on a snowboard that is almost always attached to a rider's feet. It features in the Winter Olympic Games and Winter Paralympic Games. Snowboarding was developed in the United States, inspired by skateboarding, sledding, surfing, and skiing. It became popular around the globe, and was introduced as a Winter Olympic Games, Winter Olympic Sport at Nagano, Nagano, Nagano in 1998 Winter Olympics, 1998 and featured in the Winter Paralympic Games, Winter Paralympics at Sochi in 2014 Winter Paralympics, 2014. , its popularity (as measured by equipment sales) in the United States peaked in 2007 and has been in a decline since. History The first snowboards were developed in 1965 when Sherman Poppen, an engineer in Muskegon, Michigan, invented a toy for his daughters by fastening two skis together and attaching a rope to one end so he would have some control as they st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cordillera Del Paine
The Cordillera Paine is a mountain group in Torres del Paine National Park in Chilean Patagonia. The cordillera is located north of Punta Arenas, and about south of the Chilean capital Santiago. It belongs to the Commune of Torres del Paine in Última Esperanza Province of Magallanes and Antártica Chilena Region. No accurate surveys have been published, and published elevations have been claimed to be seriously inflated, so most of the elevations given on this page are approximate.Biggar, John, 2015. ''The Andes: A Guide for Climbers'' (4th edition, ). Several elevations given by this authority are much lower than those given by other authorities, and the higher elevations are not supported by official Chilean IGM maps. ''Paine'' means "blue" in the native Tehuelche (Aonikenk) language and is pronounced ''PIE-nay''. Peaks The highest summit of the range is Cerro Paine Grande. For a long time its elevation was claimed to be , but in August 2011 it was ascended for the third ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angle Of Repose
The angle of repose, or critical angle of repose, of a granular material is the steepest angle of descent or dip relative to the horizontal plane to which a material can be piled without slumping. At this angle, the material on the slope face is on the verge of sliding. The angle of repose can range from 0° to 90°. The morphology of the material affects the angle of repose; smooth, rounded sand grains cannot be piled as steeply as can rough, interlocking sands. The angle of repose can also be affected by additions of solvents. If a small amount of water is able to bridge the gaps between particles, electrostatic attraction of the water to mineral surfaces will increase the angle of repose, and related quantities such as the soil strength. When bulk granular materials are poured onto a horizontal surface, a conical pile will form. The internal angle between the surface of the pile and the horizontal surface is known as the angle of repose and is related to the density, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravity Current
In fluid dynamics, a gravity current or density current is a primarily horizontal flow in a gravitational field that is driven by a density difference in a fluid or fluids and is constrained to flow horizontally by, for instance, a ceiling. Typically, the density difference is small enough for the Boussinesq approximation to be valid. Gravity currents can be thought of as either finite in volume, such as the pyroclastic flow from a volcano eruption, or continuously supplied from a source, such as warm air leaving the open doorway of a house in winter. Other examples include dust storms, turbidity currents, avalanches, discharge from wastewater or industrial processes into rivers, or river discharge into the ocean. Gravity currents are typically much longer than they are tall. Flows that are primarily vertical are known as plumes. As a result, it can be shown (using dimensional analysis) that vertical velocities are generally much smaller than horizontal velocities in the curre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
