### formation:

Glacier
* Explain the process of glacier ice formation.
* Many glaciers deepen their valleys more than their smaller tributaries.
* Most glaciers flow along topographic gradients because of their weight and gravity
  - move just millimeters each year
* Some glaciers advance, while some others recede.
* Some glaciers are as small as football fields, while others can be over a hundred kilometers long
  - too large to measure accurately, and others are simply too unpredictable
  - very large
  - formed on land move downslope to where they meet the sea
  - tend to extend in many different directions.
  * are the largest sources of fresh water on Earth. The largest bodies of salt water are the oceans
* absorb all the other colors except blue which is reflected back.
* accumulate snow in the Zone of Accumulation.
* advance and retreat very slowly while floods ravage the land very quickly
* affect the topography of the land in some areas.
* also add to the landscape by depositing materials
  - can exist in areas that most people consider warm
  - carve very distinctively-shaped valleys
  - is home to wolves, mountain lions, and mountain goats
* also move by sliding along on meltwater that forms under the ice
  - through basal sliding
  - serve as a barometer of our everchanging climate
  - sets fruit quickly on trusses close to the ground
* are able to flow, though they are solid.
* are also abundant on certain islands in polar regions and in some high mountains
  - dangerous
  - very important to the stability of the environment
* are an important indicator of climate change
  - part of the Canadian landscape
  - blue in color
  - blue, clean snow is white, vegetation is red and bare rock is brown
  - bodies of ice that form from snowfall, and flow downhill under the pull of gravity
  - broken into zones based on surface snowpack and melt conditions
  - categorized by their morphology, thermal characteristics, and behavior
  - considered among the most sensitive indicators of climate change
  - deep layers of ice that can move slowly across the land like a great frozen river
  - extremely large, moving rivers of ice
  - found on every continent except Australia
  - gravity-driven
* are huge pieces of ice that stay frozen all the time
  - sheets of snow, ice, and rubble that the ice picks up as it travels
  - important means of erosion over long periods of time
* are in fact very sensitive to environmental change
  - retreat on every continent
* are large areas of ice that cover the land
  - masses of ice that are currently moving or previously been moving
  - more sensitive to changes in temperature than to any other climatic element
  - often major tourist attractions
  - one slow power working on the rock of mountains
  - particularly impressive and massive in Antarctica
  - permanent ice features in mountainous areas
  - poor sediment sorters because they move anything in their paths
  - predominant only on the High Arctic islands
* are present along with many ponds and abundant swift cascading streams
  - in a variety of locations around the world today
  - rivers of ice, which accumulate snow at high elevations and melt at low elevations
  - sensitive to changes in temperature and snowfall
  - sentinels of climate change
  - slow-flowing rivers of ice
  - solid ice, so unlike water, they can carry pieces of rock of any size
* are systems of flowing ice that form where less snow accumulates each year than melts
  - form where more snow accumulates each year than melts
  - therefore sensitive indicators of climate changes
  - thick ice that results from compaction and crystallization of snow
  - truly rivers of ice
  - unique in that they carve a whole valley into a U shape
  - very efficient at transporting materials, so glacial till is typically well sorted
  - vitally important to the region's ecology and hydrology
  - what make a lake a Finger Lake
* are, in a nutshell, huge pieces of ice
  - there- fore, indicators of climatic variations
* arise from the accumulation of snow crystals.
* become positive physical images in both literature and religion.
* begin forming because of snowfall accumulation
  - life as snowflakes
  - to form when snow remains in the same area year-round and transforms into ice
* break off at the water and form icebergs.
* calve without warning, posing extreme danger from falling ice and cresting waves.
* can also dig gorges into the land as they advance and retreat
  - forms hills called eskers and drumlins
  - help to generate hydroelectric power
  - leave relict populations at high altitudes that remain ice free
  - occupy more enclosed areas
  - be found in a variety of locations, they virtual exist on every continent
  - carry extremely large boulders
  - cause erosion and carry material from one location to another
  - flow because they are made of ice
  - have an enormous effect on sea level around the world
  - perform to erosive functions - they pluck and abrade
* carry debris on their surfaces in conveyor-belt fashion.
* carve paths between mountains and descend to the valley floor
  - valleys and push up stony ridges called morraines
* contain two zones of ice flow.
* cover about six million square miles which is about three percent of the earth's surface
  - much of the mountain's summit and sides
  - one-eighth of the land
* crash into the sea and the magnificent polar bear roams the pack ice.
* creep down many valleys.
* crush rock into extremely fine particles called glacial flour.
* descending to the water s edge give birth to sapphire blue icebergs.
* develop from severely compressed snow in deep hollows in mountains called corries.
* do odd things sometimes.
* eat their own offspring.
* exert massive forces on the earth and underlying rocks.
* exist in all parts of the world
  - where, over a period of years, snow remains after summer's end
* feed rivers, which are used for irrigation
  - the deep cold lakes that continually feed the flow
* flow very slowly because of their weight.
* form because snowfall in the high mountains exceeds snow-melt.
* form in areas where the temperature dips below zero
  - mountains and move down mountain valleys until they melt
  - places where more snow falls than disappears
* form on land as a result of a net accumulation of snow over thousands of years
  - of an accumulation of snow over thousands of years
  - only near the poles
  - over time and then change the appearance of the land by erosion
* form when more snow accumulates each year than melts
  - there net accumulation of snow and ice from one year to the next
  - where the accumulation of snow and ice exceeds ablation
  - wherever snowfall exceeds melting over enough years to make a pile big enough to flow
* generally flow over the land surface along a path of least resistance.
* glide past, carving out foothills and river basins.
* glisten on their upper slopes.
* grind up rocks and scrape away the soil.
* grow and shrink due both to natural variability and external forcings
  - in response to changing climate
  - with small fluctuations in climate
  - or melt in relation to climate, acting as indicators of climate change
  - when winter snowfall exceeds summer snow melt and decline when the opposite occurs
* have a snow budget, much like a monetary bank account
  - dark, long bands that can be seen on the sides and top called moraines
  - tremendous effects on the hydrology of streams
* however can move uphill for long periods of time, covering large distances.
* inch across the continent, cracking and breaking the ice.
* includes moraine.
* is known for having a high density of grizzly bears
  - one of the world's primary sources for plain industrial bearings and bearing materials
  - the only national park on the main line of a transcontinental railroad
* keep water in ice out of circulation thousands of years.
* like to flow downhill.
* look best when the sky is overcast.
* make the mountains sparkle with blue ice.
* melt in Antarctica
  - more on hot, sunny days
* move by two main processes, internal deformation and basal sliding
  - downhill due to the stress of their own weight
  - faster
  - much more slowly than rivers
  - quickest in their mid-sections on the surface
  - very slowly, but can carry large amounts of rock debris
* move, or flow, downhill due to gravity and the internal deformation of ice.
* occupy most of the valleys at higher elevations.
* occur at high elevations, where winter snowfalls exceed the snow lost from summer melting.
* pick up rock debris as the ice flows along
  - material by means of abrasion
* primarily move forward by the process of A. free fall.
* range in length from less than the size of a football field to hundreds of miles long.
* recede and advance.
* refuge for many animals native to the United States.
* require very specific geographical and climatic conditions.
* respond slowly to changing climatic conditions, providing a long paleoclimate record
  - to both pronounced and subtle changes in climate
* rest in snowy repose, while chilled streams careen down from high ridgelines.
* shape the landscape in a process called glaciation.
* shove their way through solid rock to the coast to spawn.
* slowly flow downhill or toward the oceans, carving out the landscape as they go.
* spread a murrain over the land.
* start to form on continents from the buildup of snow.
* still exist in Canada in the Rocky Mountains and in the high Arctic.
* surrounding the edge of Greenland begin to melt, adding billions of gallons to the oceans.
* tend to be much, much wider than rivers
  - grow when the Earth has many cool summers that fail to melt back the winter snows
* terminating in the sea periodically break off, or calve, forming icebergs.
* transport an enormous amount of sediment.
* typically follow a seasonal pattern of advance and retreat
  - lose only a few inches of ice per year
* usually deposit their load in the ablation zone where ice is melting.
+ Glacier, Appearance
  * Glaciers are blue in color. This is because water is very good at absorbing light. Only the strongest light, with the most energy, is able to escape. Blue is the color of light that has the most energy. Because of this, blue is the only color of light that can escape without being absorbed. The thicker the glacier is, the more blue it appears
  - Effects: Landforms
  * Glaciers are very important. They have a large effect on the environment. They do this because they are very large and heavy. When they move, they erode mountains and land. Also, since they froze long ago, snow crystals and air bubbles inside are kept in good condition. These can provide a large amount of information for scientists