Ice needle phenomenon. Gas escaping?

[makamwalker]

Hi all. My name is Mike, and I live in Sandy, Oregon; the great Pacific Northwest! As some may be aware, our weather can change rapidly and dramatically. As it just has, our temperature just dropped from 40s to 20s and colder with lots of freezing rain and snow seemingly overnight. With this recent weather event, I found something of interest in my backyard. Please follow the link below to see the many photos I took of this phenomenon. I'm trying to figure out what might have caused this. It formed in an area where I had attempted to dig a hole, but found that the ground had too much clay in its composition, and so abandoned the plan. I only dug about 3 or 4 inches into the ground. I'm guessing that some sort of gas was escaping from the ground which explains the many air bubbles in these vertically frozen ice needles. Any suggestions or ideas are welcome!

 

https://plus.google.com/115567272894520552544/posts/9JE4UNqYkvy

 

P.S. I have deducted on my own that it can't be an organic compound decomposing because the temperature would of course slow that process down to all but a screeching halt. Keep in mind that the outdoor ambient temperature is in the 20s, teens and colder, and in the Pacific Northwest there is MUCH humidity in the air. I'm very curious to hear your thoughts!

[Acme]

It's not gas escaping from the ground that causes the needles, and the bubbles are due to air coming out of solution with the water as it freezes. The needles are a type of frost heaving.

 

Frost heaving

Frost heaving (or a frost heave) is an upwards swelling of soil during freezing conditions caused by an increasing presence of ice as it grows towards the surface, upwards from the depth in the soil where freezing temperatures have penetrated into the soil (the freezing front or freezing boundary). Ice growth requires a water supply that delivers water to the freezing front via capillary action in certain soils.

...

Needle ice is essentially frost heaving that occurs at the beginning of the freezing season, before the freezing front has penetrated very far into the soil and there is no soil overburden to lift as a frost heave.[5]

Needle ice

 

Needle ice is a phenomenon that occurs when the temperature of the soil is above 0 °C (32 °F) and the surface temperature of the air is below 0 °C (32 °F). The subterranean liquid water is brought to the surface via capillary action, where it freezes and contributes to a growing needle-like ice column....

PS I notice this phenomena -and have photographed it as well- in my garden soil fairly often. I'm just across the Columbia from you. Here's a shot from last year.