Journey to the Center of...30,000-Year-Old Ice

Permafrost--perennially frozen ground--is a fact of life up here.  It affects everyone in some way from building foundations to roads heaving to having ice cold water straight out of the tap (that last one I really like!).  Engineers in this part of the world have been battling the effects of permafrost (especially when it melts due to, say, a road bed laid over top of it) and trying to understand permafrost for as long as people have been building here.

This sign is located on the Steese Highway just south of the small town of Fox, AK, almost 10 miles north of Fairbanks.  For a month earlier this year we hauled drinking water from a natural spring in Fox, so we saw this sign quite a few times.  Every time we passed it, I thought to myself and often said aloud to my husband that I would love to see that. This Permafrost Tunnel Research Facility is a joint facility between the US Army Corps of Engineers and the University of Alaska-Fairbanks.

This past Saturday and Sunday, they held their first open house ever in their almost 50 years of existence.  Of course, we jumped at the chance to tour this tunnel.  They apparently were not sure how many people would show up for it.  They were overwhelmed by the outpouring of interest from the community and tourists.  I don't know the stats for Sunday, but they had to turn away at least 250 people on Saturday because they could only take about 475 people through the tunnel on their scheduled tours.  Apparently, if we had arrived much later than we did (about half an hour after they opened), we would have been turned away as well.  Fortunately, however, we both got to tour the tunnel and it was well worth the wait we had.

They actually cool the tunnel down to 24 degrees to prevent any of it from thawing.  Normally permafrost is just a few degrees below freezing.

Ice wedge

Junction of that ice wedge with other wedges

An ice wedge is a narrow piece of ice extending from ground level down into the ground several yards, usually growing every winter.  The wedges usually form in a polygonal pattern, causing the junction pictured above.  If you want to learn more about this (I'm a geology nerd, so it totally fascinates me), the tunnel's page about ice wedges has a lot of information, diagrams, and more (better than ours) photos from inside the tunnel.

Striation in the ice wedge.  These wedges are predicted to be 30,000 years old, but have stopped growing. 

Close-up of the ice surface. 

In addition to the tunnel itself, they had displays and scientists on hand to teach more about permafrost, what they've found there (mammoth bones, bison bones, etc.), and techniques for dealing with building on and in permafrost.  One of the most interesting displays was actual chunks of ice from ice wedges in the tunnel.  You could even touch it and pick it up.  Seeing it up close and backlit (see the light there?) was really something else because you could see all the sediment from all the years of growth.

We really feel so blessed to have had the opportunity to see something so rarely seen by the public and, as part of their purpose in this open house was to gauge public interest, I really hope they do it again sometime and even work toward having regular public tours.