Avalanches are just one of many natural disasters that kill people every year. The difference to Alaskans is that this disaster hits a little closer to home than most. The fear of hurricane and tornado are not existent in my region, and even earthquakes are seen more as a little shake then any threat. Physics plays a huge part in avalanches, thermodynamics, statics, and gravity are just a few elements of these disasters. The map above confirms that Alaska is at high risk for avalanche. As a result of this threat, learning about avalanches is a necessity when recreating or working in high avalanche areas.
In order to better understand Avalanches, it makes sense to first learn about what avalanches are compose of, snow. Snow forms when atmospheric conditions cause water vapor to condense. However, it is obvious that all snow doesn't have the same structure.
The density of fresh snowfall is dependent on both the kind of snow crystal and the air temperature. In cold, calm conditions the snowfall is the lightest. While in warmer climates, where graupel and needle crystals fall, the snowfall is the densest.
When looking at a cross section of snowfall it is often evident what weather conditions formed the cross section. This is due to the different densities and structures of the snow layers. The bonds between snow layers are large factor in avalanches. If there is a weak bond between layers, the top layer can easily slide off the bottom layer. When this happens it is called a slab avalanche. Other layering characteristic will create other avalanches and hazards, such as ice avalanches and cornices.
Whenever traveling in avalanche country it is important to be aware of your environment. Steep gullies and wide plains are perfect paths for avalanches. Ridges and unconformities in the terrain may help to slow down an avalanches speed. The severity of an avalanche is directly related to the terrain in which it happens.
One of the most important factors to consider is the slope of the mountain or hill. Most avalanches occur between 20 and 50 degrees like the diagram above shows. However, the largest avalanches occur between 30 and 45 degrees, and the areas which have the greatest frequency of avalanches are between 35 and 40 degrees.
Traveling north on an Indian trail, the first sign of the area’s cataclysmic past would have appeared out of place from the rolling hills typical of the Western Pennsylvanian landscape. Peering down into a valley over 400 feet deep, the mighty gorge was littered with enormous boulders, framing the Slippery Rock Creek. These relict boulders of rock types foreign to the area are known as “glacial erratics” and are indicative of the strength of the encroaching glacier. As defined by the National Snow and Ice Data Center, “Glacial erratics are stones and rocks that were transported by a glacier, and then left behind after the glacier melted. Erratics can be carried for hundreds of kilometers, and can range in size from pebbles to large boulders.
Early this February the states surrounding the great lakes in the northeast were pounded by lake-effect snow storms. Some areas saw more than four feet of snow. These states are accustomed to lake-effect snow storms, but it has been some time since they last saw one of this magnitude. Some areas saw up to 140 inches in less than twelve days. The storm was accountable for 35 deaths. (msn.com 2007)
Often, the effects of Mountain top Removal are disastrous, the wildlife habitat is damaged and vegetation loss usually leads to numerous floods and landslides. When explosives are used, fly rock, ...
Lassen Peak has the highest known winter snowfall amounts in California. There is an average annual snowfall of 660 in, and in some years, more than 1,000 inches of snowfall at its base altitude of 8,250 feet at Lake Helen.
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...
Mountains were formed across every continent due to the shifting and folding of Earth’s crust, some formed about 350 million years ago
As mountain ranges began to reappear, streams and rivers became more vibrant with rushing waters transferring boulders and gravels to different places on the surface of Earth. Water is known to be one of the most significant factors of the Exhumation of the Rockies; however wind is thought to have played an important role in the removal of the mountains from the depths of debris as well. As John David Love has said, “Wind erosion has tremendous significance in this part of the Rocky Mountain region” (McPhee 60). Consistent southwest winds, blowing in the same direction throughout each time period of the Earth’s history, picked up thousands of feet of debris from the surface of the Earth and carried it away into the Atlantic Ocean. The work of erosion through water and wind has given the landscape its
Lake effect snow is a very interesting mesoscale convective phenomenon that occurs mostly during the heart of the winter season and adds greatly to the annual snowfall that areas
would snow up to depths of eight inches and sometimes it would rain and hail for
The geologic history of the Rocky Mountains has come about as an aggregation of millions of years. Briefly speaking, the formation of the Rockies transpired from hundreds and millions of years of uplift by tectonic plates and millions of years of erosion and ice have helped sculpt the mountains to be what we see today. The majority of the rocks that make up the Rocky Mountains began as simple shale, siltstone, and sandstone accompanied by smaller amounts of volcanic rock which formally built up for approximately 1.8 to 2 billion years in the ancient sea. By 1.7 to 1.6 billion years, these sedimentary rocks got caught in the zone of collision between parts of the earth’s crust and its tectonic plates. The incredible heat at the core of the mountain range then recrystallized the rock into metamorphic rock by the heat and pressure of the collision forces. Eventually, the shale would be transformed into both schist and gneiss. It is believed that granite found in the Rocky Mountain parks came from pre-existing metamorphic rock created shortly after the formation of the earth. Ultimately, the high mountains of the period were slowly eroded away to a flat surface exposing metamorphic rocks and granite. This process occurred around the period of 1,300 to 500 million years ago. This flat surface would become covered with shallow seas and rocks from the Paleozoic period and would be deposited and eventually cover the surface. There is...
“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.
When it comes to cars, there are plenty of safety features incorporated by manufactures to ensure a smooth and safe ride. Some of these features seat belts, airbags, and antilock brakes. Nowadays, there have been great improvements to technology within cars to aid in the avoidance of collisions altogether. Examples of these technologies include blind spot detection, backup cameras, 360-degree cameras, and autonomous driving. Many of these newer safety features are there to avoid collisions. However, whenever a collision does occur, there is not much there to protect passengers in the rear of the car. Looking into this, there is evidence that shows that rear passengers do obtain injuries in collisions and pose the threat of contributing to others injuries. So, why are rear passenger airbags not standard in your vehicle?
To begin with, the landing of the snow on the road caused many damages to them. This was because the levels on which the roads were raised were in different proportions. This, therefore, prevented lack of flow to be experienced on the roads. Moreover, the cracks that were observed on the roads came about because of the difference in the temperatures of the country.
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.
U.S. Geological Survey. Worldwide Overview of Large Landslides of the 20th and 21st Centuries. 6 December 2010. 3 February 2011 .