How long do ice holes stick around?

A student in Julia McFarland’s class at Egan Junior High asked “how often do you have to redrill the holes in the ice.”

The answer is… well it depends. Two factors really impact this 1) how often you tend to it and 2) the time of year. Early in the season (around august through November) the ice is still thickening and it is cold out. In conditions like this it can take as little as a week until it is very difficult to re-open the hole to below. A chain saw will still work but at some point the ice has grown on the sides that one can’t fit down the hole ever if there is open water at the top. If we go out and chip it open every couple to four days, even at that time of year, then the hole will stay good for about a month. However, a hut makes a big difference and we dove out of the same hole that we drilled at the end of August until December with very little work (although we were in and out of it all the time.) So anywhere from a few days to 4 months.

This time we needed a hole to stay open that couldn’t be tended – the solution? A BIG hole. This hole has been open for over a month and not covered up. You can see that we (and I use the Royal we – meaning mostly Terril and Martin) have been chipping only half of it as it was so big. However this is also possible because of the time of the year


This is the bottom of the ice right now, and what you can see is many ruts and lines of erosion as the water is slowly melting it away from below. This creates a place for fish to live and algae to grow but also means that we don’t have to worry too much about the ice actually sealing up the hole again. On windy days it gets a frozen crust, but nothing that a bit of hard work can’t crack back open.

Ice thickness and temperature

Julia McFarland’s 7th Grade science class from Egan Junior High School from Los Altos, CA asks:

How thick is the ice and when you jump in how cold is it?

The ice is currently right around 1.4 meters thick or 4- 5 ft.  The water is -1.8C or 28 F.  This is two C below freezing and as cold as seawater gets before it freezes.  As soon as we jump in all of our skin that is exposed, which is only our lips, goes numb immediately so it really is not that cold after the initial shock.

You can see here that we are pretty much entirely covered up. The little sliver around our lips is all that is exposed.


The ice is slowly thickening during this time of year and at one of our dive spots it has gotten to around 12 feet.  A lot of that ice is unconsolidated “brash” ice which means if we touch it it moves more like a slushy or more like snow than ice.  Starting in mid to late November the weather warms where the sea ice is no longer thickening and it will eventually break out.  This normally happens  every year but every once in a while the sea ice will stay here for a few years creating very thick ice, in the past decade we have seen 12-18 ft of ice where we have 3 ft this year.


This is what the bottom of 12ft of ice with 6ft of snow on top looks like.the jagged ice around the side is the brash ice.

Ask Scientist: How cold is the water?

Dear Polar Scientists,

I like to watch Frozen Planet on tv because it’s interesting because there’s lots of strange creatures that live in the arctic. My favorite is the Woolly Bear caterpillar.


My question to you is; What is the temperature of the water where you are and how do you protect yourself from the cold water?


Stay warm!

Adelina Brown | Second Grade | Beaubien Elementary | Chicago, IL

I like the Frozen Planet too. The Icy Finger of Death Brinicle time lapse video is my favorite, and we saw the place they filmed that shot two days ago.  The water where we are diving is -1.8°C or 28°F. That’s below freezing for fresh water and the approximate freezing temperature for sea (or salt) water. However, that is still much “warmer” than the air temperature has ever reached since we’ve been here. In fact, when we drill a fresh dive hole we see steam rising off the sea water (like a hot tub) which gives a false impression of warmth.

We try our best to protect ourselves from the cold water. We have special dry suits and dry gloves for scuba diving to make sure we are in minimal contact with the water.  Our mouths are the only exposed part of our body and they go numb almost immediately. I had a glove leak once during a dive, and although I was able to finish the science goals for the dive, it was quite painful.

This is what we wear underneath our drysuits. We start with expedition weight long underwear and then add between one and two pairs of socks. I use a thin fleece pair with a thick wool pair on top. We then get in that big fleece jump suit and add another sock layer. Our feet and hands get the coldest of all.

The real secret to cold cold water diving is dry gloves. These gloves attach to our suit so our hands stay dry throughout the dive. Underneath I put a very thin fleece liner and that is it. Even with all of this, we always end a dive with cold hands – there is just no way around it since we can’t put our hands in our pockets to warm them up like someone can on the surface.

The final addition to our setup are three hoods. This is the inner one, called a gorilla mask, and the two holes are for the mask and regulator. We then put a latex hood that is attached to the suit over the top of this and then a normal cold water diving (neoprene) hood on the outside. On a good dive our hair doesn’t even get wet, however they are not all like that. The hoods are very uncomfortable on the surface but underwater we don’t even notice they are there.

Ask A Scientist: How does your equipment handle the cold?

My question is what’s the extreme ratings for the equipment you use, and since it would seem that some would be life dependent are you required to bring redundant equipment for the expeditions you go on?

Your Concerned Uncle Dave | Connor-Winfield, Aurora, Illinois


The tanks, regulators and dive computers are all provided for us down here. These are the most important pieces of equipment we use, because if your tank or tank regulators fail you won’t have access to air.

We have two regulators on every tank.  In case one fails, we have a backup on hand and a buddy with another extra regulator to follow us back to the surface. That is just one example of the redundant equipment we use to stay safe.

Luckily, these items are maintained by the dive safety supervisors here at McMurdo. It is amazing how well this equipment holds up to these extreme conditions. Just look at all the ice covering our regulators after a dive.


Ask A Scientist: The amazing shape shifting octopus

From Hill’s Hope Academy, homeschoolers in Plano, Illinois:

That first picture of the octopus is amazing!  But later you show it very small in the palm of your hand.  Does is really get that small? Or are they two different creatures?





Yes, all of the photos are of the same octopus.

What I found most amazing was how quickly the octopus was able to change not just its size and color but the color and texture of its skin too. The octopus is a master of camouflage.

Check out this Roger Hanlon video from NPR’s Science Friday and see if you can spot the octopus.

Ask A Scientist: Can anyone go to Antarctica?

These questions come from Tracey Rojo’s IB Biology class at Tucker High School in Atlanta, Georgia:

Is it possible to go to Antarctica without being affiliated with a research team at a university? And what do you do for fun?
Yes, it is possible to go to Antarctica even if you are not a researcher. The National Science Foundation contracts out many different types of job opportunities for people to come down and work. There are carpenters, electricians, janitors, dish washers, heavy machinery, fire fighters, etc. and  everyone has the most interesting background stories. We met this one guy, Sven, on the way down who used to be one of the California smokejumpers (forest fire fighters that jump out air planes to control forest fires), but he wasn’t coming down to be a fire fighter… I think he was a heavy equipment operator for the summer.

To be honest there are far more support personnel than science personnel. Most people come down to live and work here for 4-8 months, and I believe 18 months is the limit on the amount time anyone can stay on the ice. There is a minimum age 18 to work down here.

There’s a lot of amazing hikes if you want outdoor stuff and coffee house with theatre libraries, and lounges for indoor fun.

What is your housing like?  What type of meals do you eat?

Housing is a mix of different arrangements.  Some are dorm style, some buildings were left over from the old Navy days, and there are talks of modernizing all the housing soon.

There are three meals a day always at the same time so your body gets sort of trained to get hungry around these times, like it knows it is due for a feeding. An excellent team of chefs prepare different things each day and it is all you can eat.

Ask A Scientist: Under the Ice

From Tucker High School in Atlanta, Georgia:

When you dive under the ice, how long do you stay under the ice with each dive? Even with the special scuba diving gear, do you still feel cold when you are under the ice?

Each dive has it’s own mission and time can vary, but our average time has been 35-40 minutes. How long we stay underwater is a function of the amount air we take down and the depth at which we are diving. Since we only use steel 95 tanks, which hold about 96 cubic feet of air at 2400 psi, all of our dives times are regulated by how deep we are diving. We use the some of the same gas laws developed by scientists around the end of the 18th century to plan our SCUBA dives in order to make sure we have plenty of air. As you take these tanks down under water the deeper you go the more pressure there is from the water column, and as Boyle’s law states, the volume of a given mass of gas is inversely proportional to its pressure, if the temperature remains constant. Thus, the deeper you go the more ambient pressure there is and the mass of gas per breath increases because the air gets compressed to a smaller volume, which means you have fewer breathes off that one tank at 100 feet verses 20 feet. Just to be clear here, the density of the gas you are pulling out of your tank immediately goes to ambient as you are breathing through your regulator. So at depth you breathe more gas per unit volume due to the increased density, and since density increases as a function of depth, the time your gas supply will last decreases proportionally. However, Boyle’s law doesn’t account for temperature and that water is COLD. So we have to use Charles’s gas law to account for an even greater reduction of volume when we dive in ice water. There are also safety concerns about nitrogen dissolving into your blood at higher pressures, which is another important item we take into account. We have been trained thoroughly on how to take into account all these factors so that we stay well within our safety guide lines when we go below and always come back safe and sound.

Cynthia Spence photo of Rory climbing out after a dive

Our SCUBA dry suits and special dry suit underwear, a sort of fleece onesie, help keep us “warm” and dry in the ice water.  There are certain tricks you can do to move some of that warm air around your core to your hands and feet which really help to keep you from getting too cold. Stay down for any amount of time and you can feel that cold starting to sink in, but again a small price to pay for this kind of science.



Ask A Scientist: Wildlife

From Tucker High School in Atlanta, Georgia:

What kind of animals live in Antarctica? Do they live there year round?

The only animals that live at McMurdo station year round (except for humans) are the Weddell Seals. They survive the winter by chewing holes in the ice allowing them to have access to air even during the harshest antarctic storms. During the summer months, Adelie Penguins show up as well as Skua. Skua are essentially the southern ocean equivalent of seagulls except they migrate huge distances and are much nicer to look at. They fulfill the important scavenger role in the ecosystem. Later in the year we get more larger marine wildlife, including Minke and Orca whales. Emperor penguins stay to the north of McMurdo proper but occasionally show up as do a few other species of seal, including Crab eater seals. There is way more life than I can describe under the ice and we will show images of that as we continue in our research.

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Ask A Scientist: Food

From Tucker High School in Atlanta, Georgia

What kind of food is available for the scientists to eat at McMurdo Station and where is it grown?

We eat almost entirely food that is flown in or brought in by ship the year (or in some cases many years) before.  The  food is pretty amazing as a whole team of chefs make a diverse array of fresh breads, desserts, meat and veggie options and sides galore.  The real challenge is not eating too much.  Fresh salads are delivered by plane but when no flights come down these disappear from the menu.  Later in the season we will take you on a tour of the Galley and Dining area so you can see first hand.


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