Diving under ice: what you need to know


Getting ready to dive inside the tent at the ice entry location. Photo: Warrick Powrie.

Who in their right mind would want to dive under 60 cm or more of ice?

Some might think I’m not in my right mind… But late last year I was part of an month long expedition to Antarctica to undertake scientific research on the Ross Ice Shelf as part of a collaboration with several scientific research institutes. I assisted in ice diving surface support (see Dive magazine Issue 162).

Story by Warrick Powrie

I loved the thought of diving under the ice so I decided to get the right training for it. I applied and was granted a scholarship through the Queen Elizabeth Trust to do this.

Two weeks of Ice dive training lay ahead. It called for new dive gear capable of withstanding freezing temperatures: a Santi drysuit with thermals and flex 190, a Halcyon BC and an Apex MTXr extreme cold water regulator. In February this year I flew to Calgary, Canada, to undertake an ice diving course through Adventures in Scuba Calgary. I also aimed to become an instructor in this specialty so needed at least 10 dives under the ice.

Lake Minnewanka

During the summer the lake where we were to do our dives, Lake Minnewanka, just out of Banff, is beautiful. Loads of tourists flock in for the stunning views of the Rockies. During the winter it’s a mecca for skiing and other snow activities.

After spending a few days acclimatizing to the winter chill (-23°C) then meeting the support crew (with a ratio for this course of 2 to1), we proceeded to head out and set up our dive site. This was an experience in itself. The trudge through 30- 40 cm of snow to our dive location 600 metres away took loads of energy, though fortunately we had several sleds to cart the gear and equipment.

Ice diving course site camp on Lake Minnewanka. Photo: Alan Keller.

A large ex-military tent was deployed against the elements if they got too bad. We used a wooden slat triangle to mark out our dive hole, and a chainsaw to cut deep into the ice to sort our dive entry hole through 60 cm of ice.

We’re tethered together with our buddy. Photo: Warrick Powrie.

A large circle was dug into the snow around the hole about 15m out with another at 30m, then we cleared 4-8 spokes radiating like a wagon wheel from the entry hole.

Such a pattern is cleared for two reasons: light illumination, and as a lost diver aid since, from below the ice you can clearly see the pattern to guide you back to the entry/exit hole if it is needed.

Gearing up

Gearing up for my very first ice dive was exciting. Balancing myself to avoid getting snow in the suit was a challenge. The coldness of the air makes everything freezing to touch, and keeping your feet warm becomes tricky once the nice warm snow boots are off.

Before going in we are reminded once more of the line communication signals. A thorough briefing is conducted.

A wagon wheel carved in the ice provides a guide to the entry/exit hole.

Once my buddy and I are geared up – we are first in the dive rotation – and buddy check completed, we sit on the edge of the dive hole to allow the two surface tenders do their thing; hooking on safety lines, checking all gear is attached correctly, and of course to ensure air is on.

We are all hooked on for safety. Photo: Warrick Powrie.

We have two standby divers waiting ready if an emergency should arise. Everything is set to go. I can feel the excitement rising in the dive tent. I feel my own excitement increasing. Or is this anxiety that I’m feeling? Loads of things are racing through my head.

Regulators have a tendency to free flow in freezing conditions.

We do not check our air flow until the mouthpiece is in our mouths, and we have our heads under the water slightly while on the surface to make sure our first breath is an inhale, not an exhale. Our instructor is waiting. We give the ok signal to descend.


The cold water (one degree Celsius) hits exposed skin like a sharp Antarctic blast. Lips and cheeks instantly transform into blocks of ice.

The water visibility in the lake is not great, rather green, and there isn’t much fish life. We descend and check everything is ok with the equipment. What with the poor visibility and the water so cold, the idea running in my head is that I cannot just go to the surface. My stress levels rise. I even think: what the hell am I doing this for? But very soon my 30 years of normal diving experience kicks in.

I tell myself to calm down, control my breathing, relax.

Because we are tethered to each other as a buddy pair we cannot move far from each other. Each diver has an allocated role within the dive. Diver A as the primary diver is in control of the dive; Diver B pretty much goes along for the ride, on a short tether from diver A.

We descend to take a look at old bridge pilings where several stacks of old wood lay on the lake floor a tour location. Sediment can stir up very easily and make vis worse. We avoid getting too close to the piles.

The skills set

Some skills we undertake on this course deal with regulator free flows underwater, line communications, navigation, the lost diver scenario, and what to do if a lost diver needs rescue.

After the dive, Sheila from Adventure in Scuba, is on hand to make everyone hot chocolate and really good burgers on the BBQ, with warm water provided for people to put their feet and hands in. And for any hoods or gloves they want to be toasty warm.

All 10 of the other students on the course undertake a minimum of four dives each during their training days.

Since I was doing the instructor rating I had to get in at least 10 dives over the two weeks.

It was fantastic to get in the water while other students were running through their skills and to monitor their training. It was so much fun and I can recommend this for anyone up for the challenge.

I want to thank everyone involved with my training::

  • Queen Elizabeth Trust (Ministry of Education)
  • The University of Waikato • Adventures in Scuba Calgary
  • Overhead Adventures Tutukaka (Santi and Halcyon Dealer)
  • Air New Zealand for excess baggage allowance sponsorship
  • Scuba Equipment Servicing Limited

Warrick Powrie is an Advanced Technical Officer for the School of Aquatic Science at the University of Waikato in Hamilton, New Zealand

Photo: Warrick Powrie.

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