A new perspective

Diving under the ice in Antarctica is an almost indescribable experience. Words and photos do not do justice to the beauty of the lighting down there. On this dive, Andrew and I collected bryozoans for a pilot study on trophic carbon pathways. After collecting a few larger colonies, we explored the north side of the jetty dive site. Here are some of the photos from the dive:

Despite having visited this site several times this trip, it felt like I was seeing it for the first time. Just a wee shift in perspective gave me a wonderful new outlook. I suppose that applies to many things in life… I don’t think I will ever tire of taking photos here.

A Year in the Making

A blog by Justin Smith.

Getting things done in Antarctica isn’t easy.  Even the most basic tasks require a bit of planning and preparation.  Nothing is exempt.  Life just isn’t simple or easy here at the bottom of the earth.  SCUBA diving is no exception.  The process of an actual dive down here is a story in itself.  In an attempt to stay focused, I’m going to dive (ha!) into what it took for our team of four divers to get ready for this incredible adventure and those that helped us along the way.  

5 Months before any of us would set foot on the ice a partial assembly of our team did what would be our first official training dive.  The roaring winter seas on the southern coast of Oregon can sometimes be remarkably forgiving.  This time around proved to be a confusing contrast of beautiful skies and unfortunate wind direction, making for a very brief splash in the water.  Though it didn’t prove to be an opportunity to work out any processes underwater, it did kick off the beginning of a wonderful team bonding experience.  Getting to know the team, what they’re most excited about, most concerned about, all helped us start to connect as people and build the trust that is so essential to the challenging trip we had on the horizon.    

With a few fragmented trips in between, the whole team came together again for a weekend of diving, testing camera equipment and continuing to bond.  We planned to bring an ambitious array of camera gear down to the ice.  This ranged from GoPros, fixed lens compact cameras, a large full frame Canon and various lights and strobes.  There’s no way to make yourself feel like an amateur again than by jumping into the water with a camera system you’ve never used before.  Despite all the challenges, we did end up with a handful of acceptable shots throughout the trip.  Beyond camera gear, we started to troubleshoot the actual dive equipment (actually quite important!) required for under ice diving.  This involved tracking down leaks, replacing seals and zippers, fitting dry gloves and in lots of cases just ordering new gear.  The challenge arose when we faced the reality that the dive industry was in no way exempt from the global supply chain issues everyone faced this past year.  

In comes Eugene Skin Divers Supply.  This place is somewhere in between a hardware and toy story with everything you could dream of to assemble a kit worthy of diving under the ice at the bottom of the planet.  And if they didn’t have it on the shelf, they figured out how to get it as fast as possible.  The owners Mike and Diana (along with their entire team) became critical to our success and embraced our trip with a commitment as if it was their own.  Out of stock parts were miraculously found, zippers replaced, holes sealed.  It’s safe to say there’s a 0% chance we’d have shown up on the ice prepared and on time if it wasn’t for the shop going above and beyond.

A long list of requirements had to be met before we could even get on a plane.  The equipment was one hurdle but all aspects of our certifications and recertifications fell into the lap of our steadfast Dive Safety Officer at OSU, Kevin Buch.  Over the last year Kevin tirelessly helped us work through the dive proficiency requirements necessary to be a USAP (United States Antarctic Program) diver.  Ultimately Kevin wanted us to head town to the ice feeling confident and qualified and to have a safe and successful trip.  Over the last year Kevin held CPR, O2, and First Aid classes for us, arranged practice dives and was in constant contact with us to make sure we were on track.  

The list extends on and on to those who helped us each personally as we prepared for this adventure.  We’re all incredibly grateful for our family and friends that patiently waited as we were occupied diving many weekends, pushing off social obligations to complete paperwork, and were maybe otherwise not always entirely present as our minds drifted often towards the adventure to the ice that awaited us.

Feathery Friends

For the past week or two, we have been SCUBA diving at two new sites called Cinder Cones and Turtle Rock. Access to both sites involves a 1-to-1.5-hour drive in the Pistin Bully on the sea ice towards Erebus Bay.

Video credit: Rowan McLachlan

This drive is arguably the most beautiful commute on the planet.

Photo credit: Rowan McLachlan

This journey, whilst beautiful, is not always the most comfortable! The sea ice is covered in cracks, rafted ice, and pressure ridges, all of which are quite bumpy to cross. Unfortunately, only the driver’s seat has any suspension… luckily, we all take turns driving!

Last Friday, on our journey home after a day of diving under the ice, we received an unexpected call on the radio from Central Comms at McMurdo Station:

“Pistin Bully 318. This is Central Comms on Channel 3. Over.”

“Central Comms. This is Pistin Bully 318. Go ahead.”

“Pistin Bully 318. We wanted to let you know that there are penguins on the sea ice about a mile ahead of you on the road”

“Thank you central comms!”

This is the first penguin sighting this year at McMurdo and everyone was very excited – including those working at Central Comms!

As we continued our drive, I asked Rob, who I was driving with that day whether he thought they would be Adelie or Emperor penguins – and he reckoned Emperors that had wandered over from Cape Crozier.

Cape Crozier is the most easterly point of Ross Island, as shown in the map below (FYI McMurdo Towan where we are currently located next to Hut Point on the peninsula at the bottom left of the map). Cape Crozier is home to one of the two southernmost emperor penguin colonies in the world (>1900 breeding pairs as of 2018), one of the largest Adelie penguin colonies in the world (~270,000 breeding pairs as of 2012), and one of the largest south polar skua colonies in the world (~1,000 breeding pairs) [according to Wikipedia!].

Source: https://upload.wikimedia.org/wikipedia/commons/thumb/4/43/Ross_Island_Map_topo-en.svg/1200px-Ross_Island_Map_topo-en.svg.png

As we approached, I quickly grabbed my camera and set it up with my 200 mm zoom lens. I was very excited to get to see wild penguins! As we drew closer to town, we were scanning the horizon frantically. It turned out that they were impossible to miss! Up ahead, at the side of the flagged sea ice route were two little black-and-white mounds.

As part of the Antarctic treaty, all wildlife in Antarctica is protected and it is against the law to engage in harmful interference in Antarctica of native mammals, native birds, native plants or native invertebrates. So we kept our distance and parked the Pistin Bully about 100 m away. In my frantic attempt to take photos, I jumped out of the vehicle without grabbing my Big Red jacket or gloves – both of which were really necessary today as the wind had picked up. However, at that time, I couldn’t feel the cold – I was too excited! I ran away from the Pistin Bully and away from the others to get a shot of the penguins with McMurdo Town in the background:

Photo credit: Rowan McLachlan

However, as soon as I knelt on the ground, the penguins looked in my direction, and started to walk directly toward me!

Photo credit: Rowan McLachlan
Photo credit: Rowan McLachlan

They continued to beeline my way!

Photo credit: Rowan McLachlan

The way they walked was adorable. The slow and steady waddle! The closer and closer they got, the more zoomed-in my photos were becoming. Suddenly wishing I had opted for a different camera lens! Eventually, it reached the point where I could barely fit their heads in the frame! I had no idea they were going to be this curious!

Photo credit: Rowan McLachlan

When they were about 6 ft away from me, they halted their march and surveyed me thoroughly. Watchful eyes, wing flaps, and head bobs. They were unbelievably beautiful. The yellow colors on their neck and the pink on their beaks were gorgeous. Their feathers were so intricate and shiny. Not to mention, they were adorably fat and super cute!

I was on cloud nine. Finally, I just put the camera down and enjoyed the moment.

Photo credit: Andrew Thurber

Here I was, at the bottom of the world having this incredible interaction with some of the locals. As one of the scientists who are working on the sea ice, we were incredibly fortunate to have this experience – the majority of McMurdo Citizens are not able to get this close to wildlife – and so I realize what a privilege this was. However, some folks were able to watch us from the station with their binoculars!

Eventually, I couldn’t feel my fingers anymore and my face was getting very cold from the wind. So I headed back to the Pistin Bully, backing away slowly so as not to startle them. However, they were not phased. In fact not long after I left, they started their little waddle and came right on up to the Pistin Bully to have a look.

We spent about 30 minutes watching the penguins. They were very serene and a pleasure to observe.

Video credit: Rowan McLachlan

This was definitely one of the highlights of my trip. Thank you to my new feathery friends.

Video credit: Andrew Thurber

Soothing Silhouettes

On today’s dive at the Jetty, I played around with silhouette photography. The ice hole and the sea ice cracks offer such bright light in contrast to the dark surrounding depths. Such a dynamic light environment down there! Photo credits: Rowan McLachlan

“The Camera” – Featuring Andrew Thurber
Andrew Thurber below a sea ice crack
Lila Ardor Bellucci below the sea ice hole
Panorama of the Jetty dive site, McMurdo Antarctica
Brinicles and anchor ice at the Jetty

View of dive huts from McMurdo Station

Here is a photo showing where two of our dive sites are located, relative to the shores of Ross Island and the McMurdo water intake jetty.

Photo credit: Rowan McLachlan

As you can see, the huts are located quite close to shore, but the depth of the seafloor under each hut is ~75ft (Jetty) and ~90ft (Dayton’s Wall). I really love this view across the McMurdo Sound sea ice, with the Transantarctic Mountain Range in the distance. A view to behold indeed…

Kitting Up for Antarctic Scuba Diving

We did our first dive 16 days ago (on September 7th), and since then, we have done ~20 dives! Here is a group photo we took immediately after our first full dive.

Our dive team! Left to right: Rowan McLachlan (postdoc at Oregon State University), Rob Robbins (dive safety officer at USAP), Lila Ardor Bellucci (graduate student at Oregon State University), and Andrew Thurber (associate professor at Oregon State University). Rob Robbins has been diving in Antarctica for 44 years!

The first dive we did took a long time to get ready for. The only kit we brought with us was our dry suits and thermal under-suits. Everything else was provided by the United States Antarctic Program (USAP). Antarctic waters are among the coldest a research diver can expect to experience (-1.89°C or 28.6°F in McMurdo Sound). In these temperatures, not all diving equipment can be expected to operate properly, and malfunctions can be frequent if the wrong kit is used.

USAP’s diving gear is tried-and-tested, and therefore less likely to fail compared to personal gear, which can be of various models, ages, and qualities. Diving under the ice in Antarctica is not the place where you want your gear to break! So, for this reason, our first dive was slow as we had to check, and re-check our kit, some of which we had never used before. However, two weeks later, we finally got into a nice rhythm. So, for today’s blog, I thought I would walk you through our daily routine of getting kitted up and ready to dive!

At 8:30 am, I walk from the lab down to the dive locker (the little blue building in the photo below). The view on this walk is just awful guys…

Next its time to grab a tank:

The tanks we use are 2400 psi (pounds per square inch) steel cylinders (95 cu ft or 2690 L volume). Steel cylinders are preferred to aluminum cylinders for durability in cold temperatures. Here at McMurdo, divers are required to use two fully independent first and second-stage regulators (a regulator is a device that delivers air to the diver’s mouth underwater). This is because if one freezes and starts to free-flow (i.e., purging air uncontrollably), you can easily turn off the gas to that one, pick up your second regulator and keep breathing…yay! So, for that reason, the cylinders here have a “Y” valve, as shown above.

Next, it’s time to grab the regulators:

The only regulators which are currently approved for use here at McMurdo are the Sherwood Maximus SRB 7600 first and second-stage regulators (shown above). As you can see, one of them has three hoses attached, and these are for 1) your backup regulator, 2) the air pressure gauge, and 3) the dry suit inflator hose. The other regulator only has one hose: for the main regulator. As this regulator only has one hose, valve, O-ring, etc., it is less likely to freeze and/or fail (*knocking on wood frantically*).

Next, it’s time to attach the backplate and the regulators to the cylinder:

The backplate allows us to strap the tanks to our back. This is a good time to turn on the air and check that the tanks are full by looking at the mechanical pressure gauge.

After the tanks are set up, it’s time to pack up our gear bags. All the gear is washed and hung up at the end of every day. Luckily, Antarctica is of the driest places on earth, so our gear is always dry-as-a-bone in the morning!

After loading our tanks and bags into the Pistin Bully (the tracked vehicle we use for getting out onto the sea ice), it’s time to get suited up! The first layer we wear is long underwear thermals, as modeled by Andrew below:

Next, we don our thick insulating layer.

We use The Weezle Extreme Plus undersuit – and I have to say, this thing is amazing. It’s like wearing a sleeping bag – it is SO cozy. In fact, a few months ago, I actually took this camping, and it was perfect!

After this, we wriggle into our dry suits:

We are using the DUI Yukon II suits and they are wonderful. They were made to measure and are by far the best dry suit I have ever used.

Now that we are suited up, we load into the Pistin Bully (red vehicle shown below) are begin the very long drive to our dive hut. It takes approximately 3 minutes to get there 😂

We then unload our kit into the shed. Check out this video:

When we are situated within the warm cozy dive hut, we start to get kitted up!

The first thing we do when we sit next to the dive hole is to put on our ankle weights (2lbs). The ankle weights are just to help us maintain a horizontal position (or trim) when underwater.

Next, we put on our fins. This is a very important step because if we fall into the hole, we want to be able to kick and stay afloat! Lila models this below:

Sometimes, one of us forgets to don the fins first, at which point the team will ask them “have you ever been to FINland?” or “are you sure you’re FINished?”…. sarcasm and puns-galore in the dive hut, daily 😂

Next, we wrestle into the weight belts:

We are using DUI weight harnesses with ditch-able weight pockets. Each of us is wearing 40 lbs (or 18 kg) of lead weight, and boy – are they heavy! We need this much weight to help us sink, as our Weezle undersuits are so puffy, and therefore extra-buoyant. Now is the time in the process to be extra careful: you don’t want to fall into the hole wearing all that weight, but with no tank.

So naturally, the next item we strap ourselves into is the tank-backplate/reg set-up.

But first… the most important step of the day: MAKE SURE YOUR AIR IS ON! This step is so important (for obvious reasons) that when we do it, we even call out “I am turning my air on” to let everyone else know what we are doing – and to remind them to do it too!

Once the tank is attached around our shoulders and waist, we clip the dry suit inflator hose to our suit using the chest valve. In the photos below, the silver clip in the left photo attaches to the silver valve of the dry suit in the right photo.

This inflator hose lets us add air to our dry suit, which is how we control our buoyancy underwater. We do not use SCUBA Buoyancy Compensation Devices (BCDs) when diving under fast ice here at McMurdo. So, your dry suit is the only way in which we achieve neutral buoyancy underwater. This was a first for me in my diving career – and initially, it took some getting used to – but now it is second nature!

Then we clip the mechanical pressure gauge and backup regulator to our backplate webbing to keep them from dangling/dragging on the seafloor.

The next items we don are our hoods…plural!

Your head is an area of your body where you can lose the most body heat. Therefore, we wear lots of layers to try and stay warm.

The first hood we wear is made from thin neoprene (3-5mm thickness) and is referred to as a gorilla hood (top left hood in photos above). This hood covers all our head, except our eyes and mouth. Honestly, it looks like we are about to rob a bank when we put these on. They look a bit silly, but they do keep your face warm, which is more important!

The second hood is made of thin latex and is attached to our dry suits. This helps keep the icy cold water from getting near our neck seal, and around our head.

The outer hood is a thicker neoprene hood (7 or 11mm thickness) and is purely for thermal protection.

When all hoods are donned, we put on our masks.

Left to right: Rowan, Andrew, Lila

We then have to carefully go around the silicon edge of mask and slide it underneath all the hoods. If we don’t manage to get a good seal, we would have a mask flood underwater, which would be annoying, but more importantly, horribly cold. Brrrrrr!

Next, it’s time for the dive computer. A dive computer provides all the real-time information divers need to be able to dive well, including depth, time, safety stop, and no decompression limit (NDL) data. All USAP divers must use the dive computers that are issued by the McMurdo dive lockers. Currently, they are the Shearwater Perdix AI model.

The computer communicates with an air pressure transmitter that is attached to our regulators, and therefore our computer knows exactly how much air we have left at all times.

The last step in getting suited up is our gloves. Hands are the main factor that determines the length of a dive in Antarctica – they get SO COLD! Once dexterity is lost in the diver’s hands, the dive needs to be ended quickly. For me, I can manage about 30 minutes under the ice. After that, my fingers start to get cripplingly sore, and I can’t really move them anymore. As I am usually carrying a camera, this makes it very difficult to take any more photos as I can’t even press the shutter button! More importantly, though, a diver needs to maintain dexterity at the end of a dive to be able to use their suit inflator or change to their backup regulator in an emergency.

We install dry gloves on our suits using the Kubi ring system.

With these, we can attach basically any rubberized glove to a ring. I bought the orange gloves shown above in a fishing supply store! The other ring attaches to the silicon wrist seal on our dry suits. Then these two rings push together and seal by means of a red O-ring. A simple but effective design! So long as no fluff or hairs are caught in the O-ring, we are able to keep our hands dry throughout the dive! Trust me, if there is a leak – you will know about it very quickly as you go underwater!

We insert small diameter plastic tubes under the silicon wrist seal on our dry suit to allow us to fill our gloves with air from the body compartment of our suits. This lets us equalize our hands at depth which prevents skin pinching caused by high pressure underwater, but more importantly, helps to keep our hands warm. Well… they are never warm. It helps us keep our fingers not frozen, which would be a better description!

Under the rubber gloves, we were fleece gloves. I also use hand warmers, as I get extra cold.

Regulators go into mouths, and it’s time to jump in! Check out this video of us getting into the ice hole:

The key is to twist your body enough so that the tank doesn’t catch on the wooden floor of the hut as you go down… because, ouchy.

Finally, here is the coolest video ever made. Andrew used his 360 degree-GoPro camera to film us getting kitted up and jumping into the dive hole!

Portal to Another Dimension

On September 6th, we met the Fleet Operations (“Fleet Ops”) team on the sea ice to start drilling our dive hole!

The first place where we dive is known as “The Jetty” and is located ~100m from the shores of McMurdo Station.

View of the Jetty at McMurdo Station, taken next to Dive Hut 19. Photo credit: Rowan McLachlan.

The overall process of getting the dive hole drilled took approximately 4 hours. The first step was to tow the drill and dive hut out onto the ice.

View of dozer towing drill and dive hut to our jetty site. Photo credit: Rowan McLachlan.

The dozer dragged the drill to the exact place where we wanted the hole. The next step was to attach the screw bit to the TEREX drill. The drill bit is so heavy that it could not be attached prior to towing the drill.

Attaching the TEREX drill bit. Photo credit: Rowan McLachlan

Then it was time to start drilling. Check out this video we took of the drilling process:

Video credits Rowan McLachlan and Andrew Thurber

Once the hole was drilled, we had to scoop out some of the platelet ice that had been knocked down into the hole. Turned out, that scooping slushy ice out from an ice hole using nets was a quick way to get warm on this day which was particularly chilly. When the hole was ready, the drill rig was moved away.

Photo credit: Rowan McLachlan

The next step was to tow the dive hut, carefully aligning it, so that the hole in the floor of the hut was directly above the hole in the ice.

Panorama of dive hut in position. Photo credit: Rowan McLachlan
View from inside the dive hut, looking down onto the hole in the sea ice. Photo credit: Caleb Terrey.

The dive hut is approximately 20ft long and 10ft wide. Inside there is a diesel heater to keep us warm before and (more importantly) after a dive.

Through the hole, we hang a weighted “down line” to the sea floor (the rope is ~80ft long). Along the line are various loops where we attach flashing lights (to help us find the hole when diving), an emergency air tank (aka pony bottle), and any other kit or camera equipment we want to pick up at the start of a dive or drop off at the end.

View of dive hole from below the ice with attached down line. Photo credit: Rowan McLachlan

The snow on top of the sea ice is ~2ft deep in this area, and as a result, there is very little light that passes through. This means that diving here is basically a night dive. Therefore, the flashing lights on the downline are critical for us to find our way back to the dive hole.

Skating on Thin Ice

We are currently living/working at McMurdo Station, located at the end of the Hut Point Peninsula of Ross Island, which is the solid ground farthest south accessible by ship and the most southern place in the world to SCUBA dive!

Ross Island is located within the Ross Sea, and where we dive is within the McMurdo Sound. To the south of Ross Island (top/top-left of map below) you can see the permanent Ross Ice Shelf.

Source: https://www.coolantarctica.com/schools/Antarctica-maps-ross-island.php

An ice shelf is basically a floating glacier that forms where an ice sheet flows down to a coastline and onto the ocean surface. An ice sheet is any mass of glacial land ice extending more than 50,000 square kilometers (20,000 square miles). The Antarctic ice sheet covers about 98% of the Antarctic continent and is the largest single mass of ice on Earth, with an average thickness of over 2 kilometers. The ice shelf and neighboring ice sheet (both composed of frozen freshwater) are permanent features in Antarctica and are present year-round.

Conversely, there is also transient seasonal sea ice here. Sea ice is frozen salt water that melts and refreezes every year in Antarctica.

View of McMurdo Station and Observation Hill taken from on top of the sea ice. Photo credit: Rowan McLachlan.

The extent of sea ice in a given year varies according to climate variability and long-term climate change. Antarctic sea ice usually peaks in September (the end of Southern Hemisphere winter) and retreats to a minimum in February. Check out the satellite image below showing areas of the Ross Sea covered in sea ice taken in a previous year.

Source: https://www.coolantarctica.com/schools/Antarctica-maps-ross-island.php

In a “normal” year – the size of the continent of Antarctica doubles due to sea ice growth… but not this year.

This past winter in Antarctica has been unseasonably warm. That, coupled with unfavorable storms blowing ice out of the McMurdo Sound, has resulted in the lowest recorded sea ice extent and thickness ever for this area. August 19th, 2022 (only 10 days before we arrived in Antarctica) was the first day of sea ice growth here. As this is the end of winter, the sea ice is usually well established by this point. This is not encouraging news for a team of SCUBA divers who rely on sea ice in order to dive!

So the start of this trip has been stressful. Every day we have been monitoring the weather and literally sitting, watching, and waiting for sea water to freeze. We need thick enough sea ice in order to drive vehicles out to our dive sites, drill a hole, and dive through. Without the sea ice, we can’t get to where we need to go.

Luckily, one of our dive sites is located very close to McMurdo Station, in an area where there has been sea ice for a while. But before we were allowed to work there, we had to complete the Sea Ice Safety Training course.

First, we learned about the various factors which affect the thickness of the ice.

Source: McMurdo FS&T

Ice strength directly correlates to ice temperature, which is in turn affected by air temperature. Because of this, snow cover on top of the ice actually slows ice growth as it insulates the ice from the cold air temperature. High solar radiation decreases ice growth rate. In addition, if the albedo (amount of light reflected by the ice) is low then ice growth is also reduced. Ice close to the shore tends to get “dirty” due to dust and dirt which is blown onto it from the land. The dark-colored dirt causes the ice to absorb more solar radiation, reduces albedo, and consequently slows ice growth. Finally, depending on the direction of wind and ocean currents, ice growth can be impeded if the newly formed ice is constantly being swept away.

Next, we learned about the hazards associated with sea ice.

Source: McMurdo FS&T

The main hazards which concern us are cracks in the sea ice, also known as “leads”. When driving across sea ice, first you need to spot a crack (which can be difficult if it is covered with snow), and then you need to profile it. The width and depth of the crack determine whether or not it is safe for your vehicle to travel over the crack safely without risk of falling through to the icy ocean below (which has happened before!)

The next thing we were taught was that sea ice cracks are consistently unpredictable!

Source: McMurdo FS&T

In the slide above are two pictures of the same sea ice crack, taken 6 days apart! Within 24 hours the crack increased in width by 20cm. Three days later the crack was giant (>1m wide), and then within a few days, the temperatures increased causing the ice to expand and thus the two sides of the sea ice slammed together to form what is known as a pressure ridge (Oct 5th photo). This is a great example of how dynamic and fluctuating the sea ice cracks can be.

There are three types of sea ice crack:

Source: McMurdo FS&T

Our instructor jokingly referred to the straight edge cracks as “Bob Ross” cracks, as they are lovely and clean lines! Working cracks are constantly opening and closing. Tidal cracks form close to shore and are a result of ice freezing to land and cracking as the water-level moves with the tides.

When you come across a crack, there are several steps you must follow before driving across:

Source: McMurdo FS&T

So now we know the theory about sea ice cracks and how to profile them. Time to get out there and have a look in person!

To get out onto the sea ice we traveled in a Hagglund – a tracked, all-terrain vehicle.

The team route to the sea ice in the Hagglund. Photo credit: Andrew Thurber.

After about 10 minutes of driving we come across a nice Bob-Ross-looking straight-edge crack:

Sea ice crack near McMurdo Station formed when pressure is released from one or both sides. Photo credits: Andrew Thurber (L) and Caleb Terrey (R).

Next, we need to clear the snow away from on top of the crack so that we can see the ice below. It turns out the best way to stay warm in Antarctica is to grab a shovel!

Lila and Rowan clear the thick snow from above the crack. Photo credit: Andrew Thurber.

Once we have cleared a strip perpendicular across the crack, it is time to start drilling.

Andrew drills the ice using a 2m flight attached to drill. Photo credit: Caleb Terrey.

The aim is to drill at several locations on either side of the crack, measure the thickness of the ice, and then calculate the effective crack width. The maximum effective crack width of a given vehicle is equal to 1/3 of the length of the tracks.

Photo credit: Rowan McLachlan

The Hagglund can cross any crack that is less than 70 cm wide, as long as the ice is at least 41 cm thick.

After the holes are drilled, it’s time to measure the thickness of the ice. For that, we use a tape measure with a linear weight at the end. The weight hangs perpendicular to the tape, so once you put it through the hole and lower it down below the ice, you can pull it upwards gently and it will catch on the underside of the sea ice.

Rowan measured the thickness of sea ice. Photo credit: Andrew Thurber.

This particular crack was in ice that was >2m thick, so it was definitely thick enough for us to drive across.

We then repeated the process with a wider, messier-looking working crack:

In this photo you can see the line of drill holes spanning the crack at Lila’s feet. Photo credit: Rowan McLachlan.

And that was it for the day! We were very excited to finally be trained and approved to get out onto the sea ice by ourselves. Thanks to FS&T (Field Support and Training) for showing us the ropes – or the drills as the case may be.

Panorama of sea ice safety training group in front of Observation Hill on Ross Island, Antarctica. Photo credit: Andrew Thurber