Looking Ahead

Landscape

Yellowstone National Park is situated in a semi arid geographical area.  The air in this area holds relative humidity with sporadic rainfall.  The average annual precipitation in the park is only 15.4 inches.  Although many people think of hot temperatures in deserts, the temperatures range from a freezing 9.6 degrees in January to a comfortable 79.6 in July.

Many rivers and lakes make up this beautiful park.  The Yellowstone River is a type of exoreic drainage because it passes through this desert area but originates from the Missouri River.  Some of the lakes here are tarns.   Tarns are lakes created in a depression as a glacier is melting.

Yellowstone River in yellow originates from the Missouri River

Landscape 1000 Years From Now

            The landscape will look quite different in the park from what it does today.  The water features will look nothing as they do today and in some instances flow in completely different areas.  Most of these rivers are meandering.  The process that will cause this change has to do with deposition and erosion.  As the water flows down the streams it deposits sediments at the point bars and will start eroding each cut bank.  Over time this will cause the river to change shape and even “move” through a different area if it creates close goosenecks that will eventually be eroded and create a cut-off.

Landscape 10,000 Years From Now

            Another water feature that will not look the same will be Yellowstone Falls.   It will have been eroded back from the point where it lies today.  As streams try to reach equilibrium, they start removing nick points and eventually begin undercutting the lower part of the rock.  As this process repeats over and over the falls will erode and move back.

Courtesy of Class Presentation

Landscape 1,000,000 Years From Now

            Dinosaurs might roam the park once again, probably not.  However, this park and parts of the United States will be drastically changed in 1,000,000 years from now due to volcanic activity.  The Yellowstone Caldera has had three eruptions with a 0.73 million-year interval.  The last eruption occurred 0.64 million years ago.  This means that if it kept in line with the eruption cycle it would be due in about 90,000 years.  If it were a volcanic eruption, lava would burn everything in its path.  Also, depending on the size of the eruption, a lot of damage could be caused by the volcanic ash. Although not fatal in most cases, it can create anxiety, and irritation of the skin, eyes, and respiratory system.

Conclusion

            Yellowstone is a diamond in our back yard.  Many people that pay hundreds of thousands of dollars to travel outside of the United States for recreation should do some research on their own country.  It is filled with spectacular thermal features, a variety of animals and vegetation and is a great place to camp and hike.  I visited the park for the first time this summer and plan to go back  and enjoy the scenery again.

References:

1. http://www.eoearth.org/article/Dry_Cliamtes__B_Climate_Type?topic=49664#gen6

2. http://www.nps.gov/yell/planyourvisit/weather.htm

3. http://clasfaculty.ucdenver.edu/callen/1202/Landscapes/Arid/AridLandscapes.htm

4. http://volcanoes.usgs.gov/volcanoes/yellowstone/yellowstone_sub_page_50.htm

5. Class Powerpoints

Weather

Using Köeppen’s classification system, Yellowstone National Park is classified as BSK.  This means it is a dry, steppe dessert area.  Although it has a definite classification, the park’s website describes its weather as unpredictable.  Weather and climate are erroneously used interchangeably.  Weather is the atmosphere’s condition at any given moment while climate refers to the atmosphere’s average condition over long periods of time.

Courtesy of Google Images

This unpredictable weather is extremely important to the many hikers that visit the park yearly.  Yellowstone’s weather and climate are a product of its location.  First, the Rocky Mountains cut across the park and have an orographic effect on precipitation, winds and temperature.  This occurs when warm moist air collides with the Rockies and is forced up the windward side of the mountains.  When it hits the lifting condensation level clouds and water droplets are formed.  At this point the temperature will begin dropping 3°F for every 1,000 feet of gained elevation.  As it goes over the mountain and descends on the leeward side it becomes a dry, warm down slope surge known as the Chinook winds.  The descending altitude will have a warmer temperature of 5.5 ° F for every 1,000 feet of descent.

Courtesy of Google Images

Second, the altitude of the park has a lot to do with the temperature as well.  The average elevation is 8,000 feet ranging from 5,282 to 11,358 feet.  Atomospheric pressure decreases with altitude.  With the decreased pressure, the air expands as it rises.  As it expands the molecules move slower and the air becomes cooler than at sea level.  This fact lead to the Environmental Lapse Rate (ELR) which states that temperature will drop an average of 3° F for every 1,000 feet above sea level.  This means that on average, temperatures will be 24° F colder than sea level.

Courtesy of Google Images

Courtesy of Google Images

References:

http://www.yellowstone-natl-park.com/weather.htm

http://www.nps.gov/yell/planyourvisit/weather.htm

http://www.yellowstonenationalpark.com/geology.htm

http://clasfaculty.ucdenver.edu/callen/1202/Climate/Weather/LCL.gif

http://clasfaculty.ucdenver.edu/callen/1202/Climate/Weather/ELR.gif

http://education.sdsc.edu/teachertech/downloads/climate_answ.pdf

http://www.google.com/search

client=safari&rls=en&q=koppen+climate+classification&oe=UTF-8&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=5NidUP6IHKX5ygHYiYCICw&biw=1152&bih=584&sei=59idUIPABcXlyQHS6YC4Cw#um=1&hl=en&client=safari&tbo=d&rls=en&tbm=isch&sa=1&q=air+molecules+in+the+atmosphere&oq=air+molecules+&gs_l=img.1.0.0l2j0i24l8.68763.74137.16.77800.19.17.2.0.0.0.216.2162.7j9j1.17.0...0.0...1c.1.2ECwYfwzBjA&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&fp=c607d488d00c2dab&bpcl=38093640&biw=1152&bih=584

Mass Wasting and Weathering

Mass Wasting and Weathering

As you drive through Yellowstone National Park, you can observe many different forms of mass wasting, as well as both physical and chemicalweathering of the landscape.  For example,  the picture below portrays beautiful columnar basalt with talus piled at  the base. Columnar basalt, a type of mafic igneous rock,  forms from the solidification of lava in a vertical feature called a dike.

Pile of talus from columnar basalt.  The countless joints, or fissures, in between the columns are very conducive to weathering.  Water will deposit in the fissures, freeze, and expand each joint a little at a time and eventually cause parts of the rock to break off.

Yellowstone has an abundance of water features allowing numerous ways for water to interact with the environment.  One way is depicted below where the overflow of water is channeled through certain areas, and over time erodes the soil away creating rills.

Rills are formed by the overflow of surface water that erodes the soil away.  They are always  located in hills where gravity carries water at a fast rate that allows it to carry the soil as it flows.

One type of physical weathering observed in the park includes alveoli, seen in the picture below.  It is a type of cavernous weathering caused by tiny salt crystals which exert pressure in the rock and eventually form these small imperfections in the rock.

The tiny holes and imperfections on the rock surface are alveoli.  Salt crystals within the rock exert pressure and eventually create the pores in the rock.

Minerva Terrace is an excellent place to see both signs of physical and chemical weathering.  Notice the abundance of white in the picture.  This is the salt deposit found within the rocks.  Salt can cause alveoli and tafoni to form over time.  Towards the middle right you notice that some of the rock is a reddish color.  The rock is probably rich in iron minerals and has become oxidized over time.  The green tints towards the top left and center left of the picture are mosses and lichens that attach to the rock with tiny microscopic “arms” and help break down the rock over time.  The white structure in the center of the picture also shows signs of pressure release because it seems as if large slabs of the rock have fallen off.  This happens due to quick erosion of rocks that were formed under great pressure.

Oxidation of rock occurs in environments where there is an excess of oxygen.  Iron will change from Fe^2- to Fe³⁺ changing the color of the rock to a deep red rust color.¹

References:

1. http://www.tulane.edu/~sanelson/geol111/sedrx.htm

2. Geography 1202 Class Notes

3. http://commons.wikimedia.org/wiki/File:Columnar_basalt_at_Sheepeater_Cliff_in_Yellowstone.JPG

Hydrothermal Features

Much of Yellowstone sits on top of the Yellowstone caldera which last erupted some 630,000 years.¹   It is this hot spot that feeds the numerous hydrothermal features located all around the park.

Mud Pots

            Mud pots are acidic features with a limited water supply.  Microorganisms which use hydrogen sulfide as energy convert the gas into sulfuric acid used to break down rock into clay.  The escaping gases causes the mud to bubble at the surface.²

Geysers

            Yellowstone is home to Old Faithful; the world’s most famous geyser.  Geysers are created by water seeping into the surface reaching a heat source such as a magma chamber heating up the rock above it.  Heated water travels back up dissolving silica in the rhyolite using it to block crevices in the rock allowing pressure to build.  As superheated water nears the surface, its pressure drops, and the water flashes into steam as a geyser.³

Hot Springs

            Hot rocks from shallow magma chamber beneath the surface heat water and temperatures rise above the boiling point. It remains in a liquid state due to the pressure and weight pushing down on it from the rock and water above it, creating convection currents that allow the more buoyant superheated water to slowly rise toward the surface through rhyolitic lava flows. Then, as the water drops near the surface, immense pressure is exerted over it with the rise of the superheated water. If released in a slow and steady manner, heat energy would give rise to a hot spring, which is the most abundant and colorful thermal feature in the park.⁴

The active hot spot under Yellowstone makes the magic happen at the park.  These great features are not only an unforgettable sight for anyone but also help tell the story of the land.

References:

¹ http://www.uusatrg.utah.edu/RBSMITH/public_html/RESEARCH/ys-geodyn.html

² http://www.nps.gov/yell/naturescience/mudpots.htm

³ http://www.nps.gov/yell/naturescience/geysers_work.htm

⁴ http://microbewiki.kenyon.edu/index.php/Yellowstone_Hot_Springs