Helicopters, zodiacs, and ROVs in Southwind Fjord

In the early hours of July 31st, the CCGS Amundsen lived up to its title - breaking through the ice packed into the fjords of southwestern Baffin Bay to get to the next site in Southwind Fjord. Having now traveled far enough north that at this time of year the sky never reaches full darkness, the arrival to the fjords was also the leg's first distant polar bear sighting - the ship's path being close enough to land and with enough sea ice nearby that there were sure to be more.

Turquoise waters in the fjord Photo by: Eugenie Jacobsen

Southwind Fjord had been visited by the Amundsen - and other scientific vessels such as CCGS Hudson and the Nunavut Fisheries Research boat MV Nuliajuk - since 2013 as the site of undersea landslides and turbidity currents, which are underwater avalanches of water and sediment. One of these landslides occurred in September 2018, between scientific cruises to the area. This made Southwind a perfect location to study the before, during, and after of such an event. With so much of northern Canada made up of fjords, understanding how, when, and where they occur is crucial to being able to mitigate any resulting tsunamis, and to plan how to avoid damage to current and future underwater infrastructure - like submarine cables for internet and electricity - for northern communities.

Photo by: Eugenie Jacobsen

This five-year long exploration of the fjord revealed a completely novel explanation for the trigger of the landslide - an iceberg. This particular iceberg was actually photographed inside the fjord from aboard CCGS Hudson a week before the landslide occurred. Satellite imagery and bathymetric mapping confirmed the iceberg collided with the sediment and triggered the collapse. This year's major scientific goal was to see the iceberg pits and the landslide itself for the first time "in person" - with the high-quality cameras of the ROV.

Zodiac trip in the fjord to take photos of the seafloor Photo by: Eugenie Jacobsen

As with any stop, there is never just one major operation at a station. On the way to the dive site, a mooring was also recovered from the fjord, which had been in the water for 2 years recording the exact timing of turbidity currents. As the ROV scanned the slope below, the Fast Rescue Craft (a Zodiac boat) was launched to deploy drop cameras at eight different sites around the fjord, ground-truthing the bathymetric maps of the area previously made by the multibeam sonar. At the same time, the ship's helicopter went out on land to calibrate compass headings retrieved from the mooring instruments collected at Makkovik and Saglek Bank.

The ship then headed back out to open sea, breaking through the ice once again to reach the waters of Baffin Bay. Though it slowed down both the transit and the intermittent operations occurring on the way out of the fjord, the ice drew most of the team outside for long stretches of the relatively warm day, to watch the ship clearing a path through the frozen vista - and keep eyes peeled for more of the ever-elusive polar bears.

Written by: Sophie Wolvin