While there are many different ways for avalanches to set up, they are all related in the sense that the snows' frictional hold on the slope has released and gravity is pulling the snow particles down. When the snow is deposited during the storm, the particles are 'bonding' or 'locking' together and creating layers of particles that are relatively similar. Every time the temperature changes during the storm, or the wind shifts directions, it has an effect on how the snow settles and may form a new layer. Some of these layers are denser than others, and some will bond nicely with neighboring layers while others may not. The better the bonding is between the layers, the more stable the snowpack is. When a weak layer is deposited, or created in the snowpack, the chances of that layer collapsing and causing an avalanche are much higher. The layer may fail due to the force of gravity, the weight of new snow on top of it, or forces from a skier or snowmachine on it. An avalanche occurs when the forces due to the previous instances become greater than the mechanical strength of the snowpack. There are two distinct types of avalanches: loose avalanches and slab avalanches. While they are structurally different systems, both can be equally troublesome to those recreating in the mountains.
Loose, or point-release, avalanches occur on slopes where the snow has simply lost its ability to remain on the slope. This is due to cohesionless snow sloughing off the surface, and picking up more snow as it falls down-slope. As the first particles of snow begin to release on the steeper aspects of the slope, they collide with lower particles, and create a fanned, triangular appearance on the slope. This type of avalanche generally occurs on slopes of 35 degrees or more and typically involves only the upper layers of the snow pack.
Slab avalanches happen when a weak layer in the snowpack fails and the cohesive layer above, separate from the rest of the snowpack and flow down the mountain. The layer that separates remains intact as a unit, and resembles a slab of packed snow flowing down the mountain. As it travels downslope, collides with objects and rolls over the terrain, it generally breaks up and is crumpled into smaller, broken pieces of slab by the bottom of its runout.
When either the weak layer fails, or the bond between the slab and the bedsurface releases, the force is drastically increased on all remaining bonds connecting the slab to the slope.
The earth is split into four layers, inner and outer core, the mantle and crust. The top of the mantle and crust make up what is like the skin of our earth (see source 2). The skin is split up like a puzzle and we call these puzzle pieces’ tectonic plates (see source 1). These plates are constantly moving and the plate boundaries (edges of the plates) move and slide past one another. Sometimes as the plates move the plate boundaries become stuck. Pressure builds up in the stuck area over time and eventually breaks. This is why earthquakes occur due to the sudden movement of the plate sliding and breaking creating a fault line to go off. The fault line is the line on which the
The heavy annual snowfall on Lassen Peak creates fourteen permanent patches of snow on and around the mountain top, despite Lassen's rather modest elevation, but no glaciers.
Before examining the Northridge event, understanding the naturally occurring hazard that is an earthquake will help to better understand exactly what happened and why it was such an important geological event. With four distinct layers, two layers, the crust and upper portion of the mantle, compose the skin that is the surface layer of the Earth. The crust is not a single, continuous piece. It is actually several different pieces, or plates, that come together to form the puzzle that comprises the surface of the Earth. These plates are in constant motion rubbing against one another. These areas, known as fault lines, where the plates rub up against one another have spots where one plate ”gets stuck while the rest of the plate keeps moving. When the plate has moved far enough, the edges unstick and is how most of the earthquakes around the world occur” (Wald, 2012). The energy stored from the friction of the two plate...
The eruptions of Mount Rainier produce lahar mudflows which are similar to pyroclastic flows except they contain more water. These mudflows carry debris of volcanic ash and boulders that produce lava flows and have the consistency of concrete flowing down a mountain (C.M. Riley). Lahars can flow up to 100 kilometers per hour and can extend out to more than 300 kilometers in distance. Because they are hard to predict, give off little warning signs, and move so rapidly through valleys, lahar slides are considered to be one of the most deadly volcanic hazards.
When we think of Christmas weather, “snow” comes to mind. From making snow angels, building snowmen, throwing snowballs, and catching snowflakes on our tongues, we anticipate living in every single moment of this Winter Wonderland. However, at any time, this perfect depiction of a Winter Wonderland could unravel unexpectedly to becoming a Winter Disaster, known as a snow blizzard. In accordance to the National Weather Service that the LIVESCIENCE website quotes of, a blizzard is a “storm with considerable falling or blowing snow and winds in excess of 35 mph and visibilities of less than ¼ mile for at least 3 hours.” The Great Blizzard of 1888 overshadowed New York City to become a city that was fully covered in snow ruins as it took its toll
Snow is a concept that only a few people really know about. It seems like most people hate snow with a burning passion. However, the true northerners praise every day that it snows; mostly because it does not happen a lot. At one point everyone that participates in a snow sport has to hope that it will snow every winter. Unfortunately, our hopes and dreams do not always come true. That was why snowmaking was developed in the 1980s and has been upgraded every year so maximum snow production is possible. The first reason was to fill in the gaps that Mother Nature left out. However, now the amount of snow we receive is drastically less than what it used to be. Instead of making snow to fill in the gaps, we have to make most of the snow we ski
“At 12:42 p.m. the air was perfectly calm for about one minute; the next minute the sky was completely overcast by heavy black clouds which, for a few minutes previous, had hung along the western and northwestern horizon, and the wind veered to the west and blew with such violence as to render the position of the observer on the roof unsafe. The air was immediately filled with snow as fine as sifted flour” (Potter). No one expected the blizzard that would soon come rolling over to create some of the unfortunate deaths. Now, the questions are what exactly happened during the storm, how are snowstorms created, and what damages it caused.
same liquid rock matter that you see coming out of volcanoes. On Earth's surface, wind and water can break rock into pieces. They can also carry rock pieces to another place. Usually, the rock pieces. called sediments, dropped from the wind or water to form a layer.
Convection currents deep in the mantle of the earth, begin to well up towards the surface. As the pressure increases, it sets the crustal plates in motion. There are different kinds of mountains - Volcanic, Folded, Fault-block, and Dome mountains. Volcanic mountains are formed when magma comes up through cracks in the Earth’s crust and explodes out of lava and ash. The Hawaiian volcanoes, Mt. Hood, Mt. Etna, Vesuvius, and Mt. Saint Helens is an example of volcanic mountains.
Mudslides usually occur in hilly areas, for an example, when there was a mudslide in Bangladesh few months back, it occurred at Chittagong. Mudslides occur when a portion of a hill side becomes too weak to hold up its own weight. This is generally caused by an intense amount of rain fall. With all of the new water introduced into the slope the content of liquid makes it so heavy that gravity pulls it downward. Although water plays a major factor in creating the mud that flows in a mudslide the real reason that the land begins to slide is gravity. What happens is mudslides redistribute soil and sediments in a process that can be in abrupt collapses or in slow gradual slides.
Hydraulic Action, when waves hit the cliff, air is forced into cracks, and then as the wave retreats this air expands explosively. Over time the cracks enlarge, weakening the base of the cliff causing erosion.
...strous. These landslides were caused by the heavy rainfall which often caused the hills being dug to give way, resulting in massive landslides. The workers cut their way through the continent with dynamite and steam shovels. These engineering maneuvers were slow and time consuming but were completed successfully (McCullough 106-108).
Diastrophism is deformation of earth’s crust, caused by folding and faulting. Convergent plate boundaries are formed through diastrophism. A convergent boundary (or a destructive plate boundary) is formed when two or more tectonic, lithospheric plates collide. There are two types of plates: oceanic (more dense) and continental (less dense). If two oceanic plates collide, subduction will occur. Subduction refers to the movement of one plate, sliding underneath another plate. The plate that is pushed down is consumed by the magma in the internal structure of the earth. When this happens, there will be a large, deep underwater trench where the subduction occurred (Mariana’s trench is an example of this). The plate that is consumed by magma causes
There are many different glacial landforms created by glacial erosion, one of these landforms is U-shaped valleys or glacial troughs. This glacial landform has many distinct characteristics. One of these characteristics is that it has very steep valley sides caused by the glacier as it moves down the valley eroding the sides of the valley by the processes of abrasion and plucking. Abrasion is when the boulders and moraine carried by the glacier rubs and erodes the valley side as it physically moves down the valley. Plucking happens when the water in the glacier freezes inside of the cracks in the individual rocks on the valley side then the water freezes and as the glacier moves the rock is plucked or torn from the valley side producing the steep side to the valley.
The interior structure of the earth is made up of crust, the mantle and core (inner core and outer core). Earthquakes occur on the crust. Crust forms the external layer of the earth surface. On the crust, the plate tectonics forces are in charge of causing the abrupt earth movements. Due to the existence of an immense temperature and concurrent pressure difference in the outer layer and inner layer of the earth, convection currents occur at the mantle. This energy results from overwhelming decomposition of radioactive substances contained by the rocks found at the interior of the earth. The developed convection currents lead to movement of lava; cold lava finds its way to the interior of the earth crust, while the molten lava which is generally hot, leaves the interior of the earth to the outside of the earth crust. These kinds of circulations occur at different locations of the earth surface and consequently results in segmentation of the earth due to movement in different directions.