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  • Atmospheric CO2 Level Tops 400 ppm
    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm rep...Read more

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    Atmospheric CO2 Level Tops 400 ppm

    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm repeatedly. Daily levels of CO2 can vary due to weather, and there are seasonal trends as well. The level of atmospheric greenhouse gases continues to increase, now over 120 ppm since the Industrial Revolution began. For more on the Keeling Curve, see http://keelingcurve.ucsd.edu/. Find out more about greenhouse gases and warming.
  • Massive Tornado Outbreak on Tornado Alley
    The week of May 19 brings dozens of tornadoes to Tornado Alley in the states of Oklahoma, Kansas, Io...Read more

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    Massive Tornado Outbreak on Tornado Alley

    The week of May 19 brings dozens of tornadoes to Tornado Alley in the states of Oklahoma, Kansas, Iowa, Illinois and Missouri. On May 20th, a massive tornado struck Moore, Oklahoma, devastating communities - destroying over 100 homes and hitting two elementary schools and a hospital - with many casualties and deaths. Our thoughts are with our friends and colleagues suffering from these storms. For more on the May 20th storms, see the NOAA Storm Prediction Center Storm Report.
  • Kansas Legislator Proposes Bill to Outlaw Sustainability Education
    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of ...Read more

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    Kansas Legislator Proposes Bill to Outlaw Sustainability Education

    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of sustainability. Here is a link to the one-page bill: http://www.kslegislature.org/li/b2013_14/measures/documents/hb2366_00_0000.pdf. See report on Bloomberg News.
When wind blows across a mountain range, air rises and cools and clouds can form.
Click on image for full size
Courtesy of CMMAP

Cloud Formation Due to Mountains

Some clouds form when air encounters a mountain range or other types of terrain. When this happens, the air will rise and cool. The cooler air is no longer able to hold all of the water vapor it was able to hold when it was warm. This extra water vapor begins to condense out of the air parcel in the form of liquid water droplets and a cloud is formed.

The types of clouds that form from encounters with mountains are stratus clouds and lenticular clouds.

The image on this page shows how winds can blow into a mountain range and then rise higher in the atmosphere. The side of the mountains where the wind starts is called the windward side. The side of the mountains where the wind leaves the area is called the leeward side.

Another way that mountains cause cloud formation is when air rises because the mountain is warmer than the surrounding air and causes the air to rise. Once the air rises, it follows the same process to form clouds as described above. The types of clouds that form in this case are cumulonimbus (and associated mammatus clouds), and cumulus.

Last modified May 21, 2009 by Becca Hatheway.

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