Friday, January 5, 2018

Heave ho !

Notice anything odd about this photo from Wednesday's walk on the Jack Lake Trail ?


Would it help if I reminded you that Wednesday was the third of January ?

Where is the snow ?


Though there is snow in many areas of Nova Scotia; there is none in my area.  

None at all. Zip.  Zilch. Nadda.

That lack of snow reveals some things I hadn't noticed before.  See the white patches in the photo below ?


Those patches represent what I call "blow holes"; the frozen breath of the critters dwelling within the holes.


Look at all the "blow holes" in the picture below.  If this was a snowy day these holes would just blend in and you'd never notice them.


These fascinating breath holes are not the only thing that I noticed;

                               some of the well-worn trails are icy and suddenly rougher than usual.


What used to be a fairly smooth trail is now all chewed up.  


Something is growing under the ground and pushing the earth up.  What could do that ?


The answer is "needle ice" !   Needle ice forms when soil is saturated with water and the air is below freezing.  Ice forms at or just below the soil surface, where water meets the colder air and freezes.  As more water from the soil moves up toward the ice through a capillary or wicking action it freezes and expands.  The ice is then pushed up out of the soil forming fragile columns of ice that poke out of the earth.   Needle ice needs a certain balance of temperature, water and soil type to develop.   The soil grains need to be porous enough to allow water to move up through them, but still tightly packed enough to retain water.

Holding a big chunk of needle ice
So we've seen "blow holes", needle ice and now for your viewing pleasure I present the amazing "dropping rocks" ...


Though it looks like these rocks are descending into the ground, things are not what they seem.


I finally found an understandable explanation*  for these rocks that look like they've dropped down into the ground.  In fact the stones have stayed still; the ground around them has moved upwards !  

When the surface froze, ice columns formed beneath that frozen layer and lifted the entire mass as a single unit.  Stones were unaffected and stayed in their original positions.   

Sooooo, the stones didn't move DOWN -- the ground moved UP !


I am continually fascinated and thrilled by the world of nature.



* https://bluejaybarrens.blogspot.ca/2015/02/freeze-and-thaw.html





16 comments:

  1. I certainly didn't know any of the things you presented here. Thanks for this.

    My relatives had their power go out and come back a couple of times yesterday. They were in the dark when I phoned -- and had the power come back on just before the end of our conversation. What a relief.

    Glad you came out this storm without any problems.

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    1. I was very lucky as many in Nova Scotia lost power. The noise of the winds were very scary.

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  2. Blow holes and needle ice! Who would have imagined? This is really an informative post, Ms. Sybil.

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    1. Thank you my sweet. I've always been fascinated by needle ice but this is the first time I noticed the heaving rocks.

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  3. This is a fascinating post! I've never seen any of these phenomena here on the prairies.

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    1. Thanks Debra. Keep a lookout for needle ice in the spring. Sometimes it's the cause of very mucky trails.

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  4. Thanks Sybil! I was wondering a couple of weeks ago why the ground in my garden was so bumpy and you've answered it! Great post.

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    1. In the Spring these areas can be very mucky because of the gaps in earth and the wetness ...

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  5. Really enjoyed this informative post Sybil. Clear explanation and great photos. What wonders will you see on your next walk?

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    1. I think that's my "wonder" quota for today Sally ... but thanks.

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  6. Wow. I have received an education in cold and ice. I didn't know these things. I wouldn't see them here. We are snow covered and freezing cold.Thanks for the info.

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    1. You may see needle ice on slopes in springtime ... I'm not sure why but it happens and makes things mucky.

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  7. Sybil, this is all so fascinating! I remember you writing about needle ice before, but not the breath holes and the stones. I want to go hiking with you!

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  8. Kelly, needle ice can also be seen in spring when the temperature of the ground and air differ ... and it can lead to such sloppy trails.

    Looking forward to walking with you too. Monday is supposed to be milder ... hint hint.

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  9. Gosh, Sybil, I have never heard of any of these things! You're quite the detective!

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  10. Thank you, Sybil! I learned some new things today!

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Thanks for stopping by. I really do love to read your comments.