For more than two decades, the Police Dive Squad has returned to Lake Alta in the Remarkables mountain range above Queenstown to train in a uniquely challenging environment – under a sheet of ice.
The dive site is remote and weather conditions can shift rapidly – from clear skies to whiteout conditions in minutes. The exercise requires a helicopter or snow groomer to transport all the diving equipment, material for shelters and - new this year - Starlink to strengthen critical communication.
“We couldn’t get the helicopter up to Lake Alta to start because of the weather, so we loaded everything onto a snow groomer – scaffold, dive gear, the lot," says Senior Constable Carl O’Donnell, Wellington-based launch crew and top-side support.
“The Maritime Unit and Dive Squad work closely together so it was an awesome opportunity to support the team on location. One of my key support roles was making a warming cup of tea as the windchill at Lake Alta dipped to -15C.”
This year’s multi-day exercise was a collaboration between Police teams and Defence Force - RNZAF and RNZN - that built diving skills along with logistics, safety systems and interagency coordination.
With six staff experiencing ice diving for the first time, the training exercise provided unique capability building for the entire crew.
Safety is paramount in these conditions. Lessons learnt from previous years, like gear freezing or the shelter taking to the sky like a kite, led to smarter set-ups and better gear management.
“You can’t just dive and hope for the best," says Senior Sergeant Bruce ‘Bad’ Adams, OC National Dive Squad. "You need systems, backups, and a plan for when things go wrong.
“Ice conditions were particularly severe this time, with a metre-thick layer that included 600mm of hard ice – so thick that even a chainsaw couldn’t cut through it completely. The team had to use chippers to finish the job.”
Unlike typical police diving operations, which often involve murky waters and low visibility, this dive was described as surreal and offered crystal-clear views with an overwhelming sense of calm beneath the ice.
“It’s like stepping into another world - you go from chaos and wind in the shelter to complete silence.”
First-time ice diver Constable Amy Love described the experience: “Freezing cold, as expected. But once you’re under the ice, it’s just silence. Very eerie, but peaceful.
“It’s one of the coolest experiences I’ve ever had, especially in Police.”
Divers faced physical challenges from the cold, with effects varying widely between individuals. Some lose dexterity in minutes, while others can last longer in the freezing temperatures.
The cold can also impair judgement so clear lines of communication were a key safety mitigation as the risk of hypothermia is ever present. The systems and processes developed can be applied to other hazardous environments, such as effluent and thermal/acidic pools.
The team worked closely with the Department of Conservation and the Remarkables ski field staff, ensuring minimal environmental impact. The ski field had closed but even in their remote location they can get the odd visit from a day-tripper.
This experience provided extraordinary opportunities for our teams to work together and highlights the diversity of roles and opportunities - especially for those who might not expect such adventures - when considering a career with Police.