Alaska Life, Science

Recognize permafrost when you see it

by Nicole Mölders
Alaskan fashion blogger Nicole in a summer work outfit in neutral colors

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 | High Latitude Style | http://www.highlatitudestyle.com
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 landscape of the taiga underlain by permafrost
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 the normal growth. It grows on a south facing slope at a 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.

multi-plex house that is damaged by melting permafrost underneath
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)
See how this house's roof looks like the back of a dachshound due to permafrost thawing underneath. #permafrostthawing #Alaska Click To Tweet

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. Thawing permafrost destroys the parking lot at the Geophysical Institute on UAF campus on a regular basis.

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

You can find another post on permafrost damage, and posts on discovering other Alaska phenomena like how to recognize a geological fault when you see it and why the light is pink in Alaska in January. When you like to read about Alaksa life style and/or are interested in Alaska insider travel tips, get a subscription to High Latitude Style to never miss a post.

OOTD – Alaska summer work outfit

style blogger Nicole donning a sheath dress for work
Summer dress c/o Lookbook Store accessorized with own brooch, charm necklace, Hermes collier de chien bangle, golden bracelet (gift from my Mom),  yellow sheer scarf and worn with own Salvatore Ferragamo Vara pumps
Fashion blogger in a sheath dress with suede utility jacket, flats, and tote
Business casual office look with sheath dress c/o Lookbook Store, own Great Northwest suede utility jacket, Ray Ban aviator sunglasses, Hermes collier de chien cuff, 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.

Photos: N. Mölders, G. Kramm

© 2013-2019 Nicole Mölders | All rights reserved

Advertisements