Why is it Colder at Higher Elevations?

The age old question: Why is it Colder at Higher Elevations? Click to view a larger photograph of view from the Nebo Loop, Photo Courtesy and Copyright Lyle Bingham
It is cooler at higher altitudes
Looking Southeast from the Nebo Loop
Photo Courtesy & Copyright 2011
Lyle Bingham

Hi, this is Mark Larese-Casanova from the Utah Master Naturalist Program at Utah State University Extension.

If the old saying that “hot air rises” is true, then why is it colder at the top of a mountain? Let’s think about it in terms inflating a bicycle tire. If we were to use a bicycle pump, it would compress the surrounding air to a greater pressure as the tire is inflated. This causes air molecules to collide at a greater rate, releasing energy in the form of heat. As a result, the bicycle pump would feel warmer to the touch.

Alternatively, if a CO2 cartridge is used to inflate the tire, compressed air is released, resulting in a cooling effect as molecules rapidly move farther apart. On a warm day, the CO2 cartridge will feel cold to the touch, even frosty. So, the greater the air pressure, the warmer the temperature.

The air around us doesn’t feel like it weighs much, but it’s obvious that it has some mass whenever a helium balloon is released. The balloon, filled with a gas that is lighter than the air in our atmosphere, floats up into the sky. If we think about the amount of air sitting on top of the ground at Utah’s lowest elevation of 2,178 feet above sea level at Beaver Dam Wash in the southwest corner of the state, and compare it to Utah’s highest elevation of 13,538 feet at King’s Peak, that’s an extra 11,360 feet of air! As a result, air pressure is about one and a half times as much at Beaver Dam Wash as it is at King’s Peak. With that increased pressure at lower elevations comes increased temperatures. In fact, with every thousand feet lower in elevation, average temperatures increase about 3.5 degrees Fahrenheit.

On average, annual temperatures are about 15 degrees Fahrenheit warmer in Salt Lake City than up at the Town of Alta, just ten miles up Little Cottonwood Canyon. Even early pioneers noticed this, and decided to settle along the warmer foothills of the Wasatch Mountains. To this day, most of Utah’s population along the Wasatch Front benefits from longer growing seasons and lower heating bills, while taking advantage of higher, cooler elevations for hiking on a summer day or skiing in winter.

For Wild About Utah, I’m Mark Larese-Casanova.

Credits:
Images: Courtesy and Copyright Mark Larese-Casanova
Text:     Mark Larese-Casanova

Additional Reading:

Altitude.org Air Pressure Calculator. http://www.altitude.org/air_pressure.php

If hot air rises, why is it cold in the mountains? Colorado State University Little Shop of Physics. http://littleshop.physics.colostate.edu/tenthings/ExpansionCooling.pdf

Joule-Thomson Effect. Princeton University. http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Joule%E2%80%93Thomson_effect.html

Utah’s basement — Beaver Dam Wash is state’s lowest elevation. Deseret News. Sept. 3, 2006. http://www.deseretnews.com/article/645197370/Utahs-basement–Beaver-Dam-Wash-is-states-lowest-elevation.html?pg=all

Western Regional Climate Center. http://www.wrcc.dri.edu/

Utah’s Glacial History

Moraine with erratics, Photo Courtesy and Copyright Mark Larese-Casanova, Photographer
Moraine with erratics
Photo Courtesy & Copyright
Mark Larese-Casanova, Photographer

Little Cottonwood Canyon, Photo Courtesy and Copyright Mark Larese-Casanova, PhotographerLittle Cottonwood Canyon
Photo Courtesy & Copyright
Mark Larese-Casanova, Photographer

Hi, this is Mark Larese-Casanova from the Utah Master Naturalist Program at Utah State University Extension.

It is amazing to see just how much of an impact the large amount of snowfall from last winter still has on the annual cycle of nature. Of recent note, wildflower blooms in the mountains seem to be at least 2-3 weeks behind normal schedule. Hiking through snow in late July had me thinking about colder times when Utah’s mountains were covered with ice that flowed as glaciers.

The most recent period of glaciation in Utah occurred between 30,000 and 15,000 years ago when Utah’s climate was, on average, up to 30?F cooler. At times during this period, much of the western half of Utah was covered by Lake Bonneville, which contributed tremendous amounts of moisture as snow throughout Utah’s mountain ranges. As the snow accumulated at high elevations, its sheer weight caused it to recrystallize into ice. Once the masses of ice became heavy enough, gravity pulled them down slope, carving out characteristic U-shaped valleys.

At the top of the valleys, where the glaciers formed, we can often find large, bowl-shaped cirques. In the Wasatch Range, the Little Cottonwood Canyon glacier formed at the top, creating Albion Basin, and reached the mouth of the canyon where calved icebergs into Lake Bonneville. The Uinta Mountains contained such large glaciers that even many of the mountain peaks are rounded.

As temperatures warmed during the end of the last ice age, glaciers receded and left behind large piles of soil and rocks, known as moraines. Terminal moraines at the end of a glacier’s path, can act as natural dams to create lakes. Enormous boulders, known as glacial erratics, can often be found discarded along canyons.

While glaciers don’t currently exist in Utah, there are several permanent snowfields in shaded high mountain areas. So, if you’re feeling a little nostalgic and missing that extra long winter we had this year, you still a chance to hike up above 9,000 feet and cool your toes in the snow.

For Wild About Utah, I’m Mark Larese-Casanova.

Credits:

Images: Courtesy & Copyright Mark Larese-Casanova
Text:     Mark Larese-Casanova, Utah Master Naturalist Program at Utah State University Extension.

Additional Reading:

Utah Geological Survey http://geology.utah.gov/surveynotes/gladasked/gladglaciers.htm

Parry, William T. 2005. A Hiking Guide to the Geology of the Wasatch and Uinta Mountains. University of Utah Press.

Stokes, William Lee. 1986. Geology of Utah. Utah Museum of Natural History.

The Amazing Uintas

The Amazing Uintas: Mirror Lake in the Unitas, Courtesy Wyoming Department of Transportation, Talbot Hauffe, Photographer
Mirror Lake in the Unitas
Courtesy Wyoming Department
of Transportation
,
Talbot Hauffe, Photographer


The Amazing Uintas: Kings Peak, Courtesy Wikimedia, Hyrum K. Wright, PhotographerKings Peak
Courtesy Wikimedia
Hyrum K. Wright, Photographer
Licensed under GNU Free Documentation License,

Hi, I’m Holly Strand.

Coming from Colorado, I’m something of a mountain snob. So while I always found Utah’s mountains to be agreeable, I admit to thinking they were somewhat petite. Then I saw the Uintas. About 200 miles long and 30-40 miles wide, the Uintas lie south of the Wyoming border primarily in northeastern Utah but with its eastern flank extending into Colorado.

There are several interesting features that make these mountains stand out in my mind.

For one thing, the Uintas are one of very few east-west trending mountain ranges of significant size on the planet. The only other one in N. America is the Brooks Range. This east-westness can feel strange to someone who orients themselves on a north-south axis. Because the path the sun follows the range instead of crossing it, my sense of direction was thrown off. Perhaps this happens to others too and that’s why we often hear about people getting lost in the Uintas.

Glaciation is another interesting aspect. The Uintas were more heavily glaciated than any other part of Utah. The most recent glacial episode was approximately 30,000 to 10,000 years ago. These Pleistocene glaciers left wide-bowl shaped valleys and scooped steep-walled cirques near the main ridge line. Nowadays, sparkling lakes, streams and meadows grace the ice-carved basins and valleys.

Speaking of lakes, even a Minnesotan might be impressed with the density of the Uinta Mountains lakes. Of course, the total number depends upon what you define as a lake. But most sources say there are between 800-1000 heavily concentrated in the High Uintas.

Utahns gets a lot their water from the Uintas. The mountains are an important source for several Wasatch Front rivers and streams including the Bear, the Weber, and the Provo. Precipitation and snowmelt on southern slopes either flow into the Duchesne River or directly into the Green River.

Because they are below 14,000 feet, the Uintas didn’t fit my Colorado-derived definition of “real mountains.” However there are 17 peaks all over 13000 feet–the highest is King’s Peak at 13,528 feet. Considering the beauty and wildness and the water features in these 13ers and their surroundings, the Uintas definitely scored with me. I’m looking forward to returning to explore some more.

For Wild About Utah, I’m Holly Strand.

Credits:


Images: Courtesy Wyoming Department of Transportation, Talbot Hauffe, Photographer
Courtesy Wikimedia, Hyrum K. Wright, Photographer
Text: Holly Strand

Sources & Additional Reading


Map of the Mirror Lake Scenic Byway, http://www.fs.fed.us/wcnf/unit/kamas/mirror_lake_scenic_byway_map.shtml

Guide to the Mirror Lake Scenic Byway, http://www.fs.fed.us/wcnf/unit/kamas/mirror_lake_scenic_byway.shtml

Biek, Bob. Grant Willis, and Buck Ehler. 2010. Utah’s Glacial Geology.
http://geology.utah.gov/surveynotes/articles/pdf/utah_glacial_geology_42-3.pdf

Dehler, C.M., Pederson, J.L., Sprinkel, D.A., and Kowallis, B.J., editors, 2005. Uinta Mountain
Geology: Utah Geological Association Publication 33, 448 p. https://www.utahmapstore.com/uga33.html

Hamblin, Kenneth. 2004. Beyond the Visible Landscape: Aerial Panoramas of Utah’s Geology. Provo: BYU

Jeffrey S. Munroe, Benjamin J.C. Laabs, Joel L. Pederson, and Eric C. Carson. 2005.
From cirques to canyon cutting: New Quaternary research in the Uinta Mountains
Field Guides, 6, p. 53-78. http://fieldguides.gsapubs.org/content/6

Kirkland, Gordon L. Jr. , 1981. The Zoogeography of the Mammals of the Uinta Mountains Region. The Southwestern Naturalist Vol. 26, No. 4.

Shaw, John and James Long. 2007. Forest Ecology and Biogeography of the Uinta Mountains, USA. Arctic, Antarctic and Alpine Research, Research 39(4): 614-628.