Sunday, January 13, 2013

All about Undercast Clouds and More

My son, Kevin, who lives in Vermont is quite the athlete.  The ski mountain in Stowe was very crowded, so rather than deal with long lift lines, he took the chair lift up and then bushwhacked his way up to the top of Mount Mansfield.  He can do this by using "skins" on the bottom of his skies.  These skins provide friction that allow you to climb up snow in the back country. Here are some photos from the Internet.

Here are a few more photos of the Internet of other people that do what Kevin does. It makes me nervous that he skies the trees, but he says he does it safely.

Kevin climbed up to the top of the "chin," which is the second from the right peak in the photo below.

When he go to the top, it was socked in with clouds. He skied part way down and captured these pictures of an "undercast."   Notice the clouds in the valley below as well as the overcast clouds above.  Kevin was sandwiched between the layers of clouds when he snapped these pictures. 

There was around five feet of snow at the peak. Notice that the clouds even cleared above and the sun popped out.  Down in the valley, it was still cloudy.

Well, I live in Michigan so I had never heard of an "undercast."  For good reason:  there has to be enough elevation change to observe this phenomenon.  When you are in an airplane above the clouds, technically you are above the "undercast."  Mountainous terrain also provides the conditions for low level clouds to form.  There has to be an inversion layer that traps the clouds in the valley.  To see them, you have to be up on the mountain.  Well, in Michigan these conditions don't exist since the most elevation change in our state is only around 1,300 feet.

Here is some information from

"Overcast is another term for a cloudy sky. Undercast is the term for a cloudy sky, UNDER the observer. How can that happen, you ask? Picture yourself on a mountain top, where that cloud deck is lower than the peak of the mountain top. Ohhhh. It all comes together now! ... A layer of moist air should get trapped underneath an inversion layer (a layer in the atmosphere where the temperature increases with height, just opposite of what typically happens). That inversion, or warm layer, is stable. It acts as a cap on the atmosphere. As moist air gets trapped below that inversion, you will have a stuck layer of cloud cover, and perhaps some drizzle. So, why undercast? Because that warm (inversion) looks to be located at about 1800'-3000' elevation...just under many of our mountain tops and mountainous areas."

Progress on completing the editing of the online rockhounding adventures continues.  I'll finish segment C of the second adventure today, with two segments left.  However, yesterday I reviewed the last two segments, which I have not looked at since spring.  They are very different than the other three segments of the second adventure as well as the four segments of the first adventure.  All of the first adventure and the first three segments of the second adventure provide background information.  To remind everyone, the segments are:

ADVENTURE 1:  The Basics
Segment A -- Building Blocks
Segment B -- Universe Formation
Segment C -- Solar System Formation
Segment D -- Earth Formation

ADVENTURE 2:  The Lake Superior Agate
Segment A -- Local Geology
Segment B -- Agate Formation
Segment C -- Rockhounding in Grand Marais, Michigan
Segment D -- Beach Rock Identification Guide
Segment E -- How to Find Agates

As for Segment 2E, which is the one many of you rockhounds are looking forward to seeing, it is very different from the books.  I use visual images to help train your eye to recognize agates on the beach.  Of course, much of the information is relative to agates found in other areas, but I focus on what is significant to beach agates found on the Lake Superior beach.

Since segments 2D and 2E are already developed using graphics, some of which are interactive, there will not be the need to create many movies.  I hope to be launching in the next 2-3 weeks. 


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