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Transcript: The Snow Wall

July 6, 2011

Hey, back to transcripts! I’m pleased that this one was next in the sequence, because it actually ties in nicely with a post I’ve been wanting to do about engineering with ice and snow.

Original audio post.

“The wind came back today. It started out calm enough, and we almost went out to make measurements. But when we called the forecasters at McMurdo, they told us that the wind was due to pick up soon, and would get to thirty knots–gusting to fifty–sometime tomorrow.

On hearing this, Mel pointed out that we were going to need to prepare the camp for the onslaught of wind and drifting snow. This meant building another snow wall.

A snow wall is both made of snow and designed to control snow. It’s simply a low structure made of snow blocks that serves to slow down the wind and make it drop its snow upwind of camp, instead of on top of us. The wind carries truly impressive amounts of drifting snow across the landscape, and it dumps it every time it gets slowed down by passing over irregularities, such as our tents. We already have two snow walls, but in the six weeks the camp has been here, the space behind them has already entirely filled with drifted snow.


A snow wall with the space behind it filled in with snow.

Most of the snow around here is extraordinarily hard-packed, and our resident snow scientists are astonished by its strength-to-weight ration. In many places, you need a chainsaw to really make much of a dent in it in any sort of efficient way. So, Mel got out the chainsaw, and cut enough blocks to make our walls.


Sorry, no chainsaw pics--this is after it gave out and Mel and Martin were cutting out the last few blocks by hand.

We had them assembled in fairly short order, so we got a little creative. Mel built an arch, I built a turret, and Martin and Ruschle spent most of the afternoon digging a snow pit and being astonished at it.


Blocks en route to their place in the wall.


Mel's arch and flowerpot (or rooster, depending who you ask.)

Martin says the snow here consists mostly of depth hoar, a sort of re-crystallized snow that’s ordinarily [that is, in more temperate regions] light and crumbly, but here is very hard—“like cement”, he says. Ordinary snow shovels would break on the first try. We use sturdy metal gardening shovels (the labels say they’re “contractor grade”) and they still have trouble. The depth hoar snow is also full of little crystalline cups and ??, quite delicate-looking for all its strength.

So, we have a new snow wall, and hopefully we’re well prepared for the coming storm. I’ll let you know how it goes. Cheers!”


Part of the complete wall.


Detail.

Oh, and speaking of timelapse…

June 25, 2011

Speaking of timelapse videos, here are a couple of others that I quite like:

Sea ice near an Adelie Penguin colony. Shows the evolution of sea ice over a period of time (perhaps late spring and summer?) Partly I just like this because the motion of the tides makes it look like the ice is breathing.

Sea stars, urchins, Nemertean worms, and other denizens of the under-ice seafloor consume a seal carcass. Narrated by Sir David Attenborough! Not for the easily grossed out or those who are unsettled by crawly things.

Svalblog!

April 21, 2011

Hello! I’m writing from Longyearbyen, in Svalbard. I actually got here yesterday afternoon, but was a bit too jet-lagged and befuddled by my ~24 hours of travel (Seattle to Newark to Oslo to Tromso to Longyearbyen) to do much.

I am surprised at how much this place reminds me of Antarctica, with its stark black-and-white scenery. One notable difference is the open water that comes right up to the land. We’ll be visiting some landfast (frozen to the shore) sea ice when we go to the field, but near the town the water is unfrozen. Our host/guide, Steve (not to be confused with my advisor Steve; maybe I will start calling him SvalSteve to avoid confusion), says this is due to warm Atlantic currents. Longyearbyen is slightly further North than McMurdo station is South, but due to its weather patterns and currents it’s notably warmer. Of course, it’s also warm because it’s Spring; the last sunset of the season was the day before we arrived, and a lot of residents will soon be leaving for the Easter holiday.

From Journey to Svalbard

Some Svalbard scenery.

There’s a surprising amount of tourism in this small city. People come to ski and hike and snowmobile and see polar bears; there are several sporting-goods stores near the short pedestrian corridor that serves as a sort of downtown. Snowmobiling appears to be a popular form of transport, with snowmobiles outnumbering cars two or three to one. Rifles are commonplace, since anytime you leave the city you’re apt to run into polar bears. (It’s rare that anyone actually shoots a bear, mind you; it’s very illegal to do it for any reason except desperate self-defense, and even self-defense cases are rigorously investigated.)



Snowmobile + rifle = typical Svalbard.

I’m here helping my colleague Bonnie do a project with the Norwegian Polar Institute–more on that later, as it sounds like tomorrow will be a long fieldwork day (we spent all of today sorting and prepping gear for it.) In the meantime, check out the blog of the other student accompanying us, Naomi to the North.

Disruptions

February 26, 2011

I am far behind on transcribing posts; I’ve been traveling around New Zealand, so Web access has been difficult to get.

Most of you have probably heard about the major quake that struck Christchurch on Tuesday. I was well away from it at the time, but since Christchurch is the “gateway to the Antarctic”, quite a few people from the US Antarctic Program were there when the quake struck. Most of them have been accounted for and are alive and well, although many of them have been left with nothing but the clothes on their backs, and several have hair-raising escape stories, including one person who apparently had to dig himself out of the wreckage of his hotel room and another who rappelled down the side of a building on bedsheets. The USAP personnel in Christchurch have been exceptionally helpful, starting up a makeshift refugee camp in the Clothing Distribution Center and adjoining flight terminal.

Meanwhile, down at McMurdo, the sea ice has broken out of the sound for the first time in a decade and a half (not because of the quake, it’s just coincidental.) Probably as a result, pieces of the ice shelf are breaking off. This may prove problematic, as the ice shelf is where the planes land to take people to and from the station. Right now the station staff are hurrying to move the road so that they’ll still be able to access the runway, in hopes that the summer crew still on station won’t be obligated to winter over.

So it’s exciting times at the USAP. Everyone’s thoughts are with the quake victims, of course, and with Christchurch as it struggles to rebuild.

I’m about to leave for a four-day hike, but I’ll be back in touch when I return.

Audio Post

January 28, 2011

Audio Post

January 25, 2011

Audio Post

January 24, 2011

Audio Post

January 22, 2011

Audio Post

January 21, 2011

Audio Post

January 20, 2011

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