Alaska Life, Science

Recognize permafrost when you see it

by Nicole Mölders
#40 #50 sheath dress for work | High Latitude Style | http://wp.me/p3FTnC-3fU
Sheath dress c/o Lookbook Store accessorized with own brooch, charm necklace, scarf and worn with own Salvatore Ferragamo vara pumps

Permafrost facts

Alaska like most areas in high latitudes or many areas at high altitude has large areas of continuous or discontinuous permafrost. Permafrost or so-called cryotic soil is defined as soil that remains at temperatures at or below 32F (0oC) for two or more consequent years. Permafrost occurs on 24% of the land in the Northern Hemisphere. It also occur on the ocean floor of the shelf of the Arctic Ocean. Permafrost holds about 0.22 per mille of the Earth’s total water.

#permafrost #Alaska landscape in Interior Alaska #travel
Permafrost area with scrubs in the foreground and crippled spruce in the background

How to recognize permafrost in the taiga

The active layer is a layer that thaws in spring and re-freezes in fall. Due to the permafrost underneath, water can not percolate in deeper than the bottom of the active layer. Thus, trees growing on permafrost cannot root deep. Consequently, in these areas, spruce trees look very under-nutritioned and remain small (see photos above and below). Often only blueberries or scrubs can grow. The ground may be very moist during summer.

#Alaska #travel permafrost landscape of the taiga in Interior Alaska
Permafrost landscape with lake and stony beach. The spruce in the background grows on permafrost, while the spruce on the r.h.s. of the photo shows normal growth. It is on a south-facing slope at higher elevation than the spruce in the background. Fairbanksans swim in the lake in summer when its water temperature is in the lower 50s (a bit over 10o). In winter, a cross-country ski trail goes over the lake

Permafrost and construction

When you build a house, street or path on permafrost, the construction conducts heat thawing some of the ground underneath. The melt-water may evaporate or run away laterally. Since the water originally was part of the soil matrix, the ice loss leads to shrinking of the ground thickness. The construction sinks and may deform.

#Alaska Multiplex affected by permafrost. The house conducted heat to the ground thawing the permafrost underneath. The water run off leading over time to the deformation of the roof (and house)
Multiplex affected by permafrost. The house conducted heat to the ground thawing the permafrost underneath. The water run off leading over time to the deformation of the roof (and house)

When there is a large ice-lens in the permafrost, a large whole can form seemingly over night when the thawed water finds a way to escape.

Best practice is to avoid construction on permafrost or provide good insulation to the ground and/or build on stalks.

Spread the word by tweeting Learn to recognize permafrost when you see it.

You can find another post on permafrost damage /a>, and posts on Alaska phenomena like faults and pink light in winter. The series Focus Alaska goes up weekly on Monday. When you like to read about Alaksa life style, get a subscription to High Latitude Style to never miss a post.

OOTD – summer work outfit

Sheath dress c/o Lookbook Store with own Great Northwest suede utility jacket, Salavtore Ferragamo vara pumps, and Jaeger tote
Sheath dress c/o Lookbook Store with own Great Northwest suede utility jacket, Salavtore Ferragamo vara pumps, and Jaeger tote

This outfit features a sheath dress dressed down with an utility jacket and low heel pumps. The scarf adds a pop of color, but picks up the color of the jacket and pumps. Thus, the color becomes part of the look that overall has a neutral feel color wise.

#fashionover50 summer work outfit in neutral colors
Back view of work outfit with sheath dress c/o Lookbook Store and own Great Northwest suede jacket, Salvatore Ferragamo pumps and Jaeger tote

Photos: N. Mölders, G. Kramm (2015)

Copyright 2013-2016 Nicole Mölders | All rights reserved

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