Thursday, January 28, 2010

Needle Ice

Dramatic changes in the weather can result in dramatic creations. Pictured is a natural phenomenon known commonly as Needle Ice. Needle Ice forms when subsurface water emerges from the ground and is acted upon by below freezing air temperatures. The recent rain saturated the surface soil and moved a short distance below ground to exit on the neighboring hill slopes. As it emerged, it began to freeze.

The large ice structures are composed of many individual ice fibers. A fiber typically begins as an ice crystal forming in association with soil particles. As the water changes to ice, the volume increases and newly formed crystals push the previous crystals away from the soil. Water continues to feed into the base of the filament and the process increases the filament length. The largest of these filaments was about 2 inches tall.

This is where the water surfaced. Ice formation continued off into the grass, but the crystals were most easily viewed on this bare spot.

Soil particles that spawned ice crystals were carried upward with the ice as the column grew. This process could certainly be disruptive to any plants trying to colonize the bare ground.

Formation of Needle Ice is like an exaggerated example of frost heave. The area between the standing ice columns offers easy access to the soil below. When the ice begins to melt, the tops disintegrate first and the freed soil falls into the fissures. Seeds that began on the soil surface are dropped into a fissure to be covered by the falling soil. In this way, the seeds are planted.

1 comment:

  1. Pretty cool, Steve. I've come across this at least once - it's a fascinating thing to see, that's for sure. Thanks for sharing.