Diving environment

A tender checks a diver's equipment beside the dive hole while another diver and dive supervisor stand nearby.
All aspects of the diver's equipment are checked by tender and supervisor before each dive. (Photo: Glenn Johnstone)
A blue hagglund on the sea ice beside a dive hole.

Antarctic diving is conducted in an extreme environment, with particular environmental conditions such as cold water and sea ice to contend with. The protocols and methods we use are, however, similar to those used in scientific diving operations in other parts of the world.

Seawater temperatures along the coast, although extremely cold, vary little over the austral summer (between -1.5°C and -1.9°C). The dry suit and thermal insulation set-up we use for diving therefore doesn't change over the summer dive season (see Diving equipment).

Diving operations are rarely inhibited by tides (the maximum tidal range is less than 2 m) or strong currents and waves. Ocean swells are practically non-existent along the Casey coast. Wind and surface temperature are, however, substantial issues for the comfort of diving personnel and the stability of sea ice.

Sea ice provides an excellent platform from which to conduct diving operations in early summer. Diving equipment can be driven right up to the dive site in over-snow vehicles such as Hägglunds, with the ice providing unlimited space in which to set up and lay out equipment.

With even a light wind, however, surface temperatures drop rapidly and dive personnel must be adequately prepared to work in temperatures of -15°C or below.

Excessive wind can rapidly break up sea ice, making through-ice diving extremely dangerous. Consequently, diving cannot be undertaken at Casey in winds exceeding 20 knots.

Casey is renowned for the fierce blizzard conditions that can rapidly descend on the area bringing strong winds, blowing snow and poor visibility. Blizzards may last several days and often cause the break-out of sea ice from the areas bays.