17-18 February 2021: HEARD the magnificent
When a meander of the jet stream couples with a southern depression in formation on the polar front, where the most intense thermal contrasts occur, it generates an explosive hurricane-force storm. Weather forecast for February 17th, Sara’s birthday: a barometer at 967 mbar, winds gusting over 90 knots and waves of 10 or even 12 m.
We are considering all possible options to be able to work despite this major contingency and not to be too late on our schedule. All the possible options are considered. Opting for taking refuge, we set off towards the northeast of Heard Island in order to make the stations planned in this area at the dawn of the next day. The scientific motivation of this exploration is to characterize the nature of the source of chemical elements produced by the erosion of the island. Indeed, exposed to violent bad weather, Heard (a small Australian island with an active volcano culminating at 2750 m) and its small neighbor MacDonald (which we may see on our return) are suspected of fertilizing the waters of the Kerguelen plateau by releasing nutrients and trace metals. This has yet to be demonstrated with the analyses of water, particles, sediments and tracers. We get as close as possible and the engines stop: wind gusts with impressive accelerations due to the effects of the island’s relief on the local aerology, but we are in a rather comfortable position to sleep. In spite of the bad weather and thanks to the exceptional mobilization of the scientific teams and the crew, we carry out a series of pumps, “clean” as well as “standard” CTD-rosettes and coring in an intense and feverish atmosphere because sampling in shallow depths means frequent round trips!
And all this in an incredible landscape view. In the early morning, Heard still lets itself be desired, we can only see parts of it through windows in the clouds and mist. But the mist seems well installed. At 1pm, we leave to the north-west of the island to try a second station. Another view of the island, a small isthmus of multicolored rocks is slowly being discovered. Here again, conditions tough enough to deploy the CTD-rosettes and to carry out coring (ah the small cores of Manu and Elena!). Intense atmosphere on board. The wind turns, strengthens a little, the conditions seem to degrade again, we decide to leave towards our initial shelter. It is then that the sky changes under the roaring winds and the white sea. In an instant, the island is revealed in a blue and green light, beautiful contrasts with the glaciers falling into the sea. A magical, euphoric, electric moment on board, where despite the cold and the wind, everyone remains on deck admiring this unique spectacle. Heard the magnificent thousand times photographed. At her feet, the gusts of winds that never stops projecting rainbow sprays. And finally, the volcano offered us a plume of smoke! An incredible day that will remain engraved in our memory. There are moments in life when time has no meaning or duration. A few seconds, perhaps minutes of euphoria where everything stops, the spirit so empty and so alive at the same time, anesthetizes or overflows the senses with pure beauty. Heard the magnificent, thank you!
Authors: Catherine Jeandel, Hélène Planquette et Christophe Cassou.
