One of the features of the Southern Ocean is the absence of land in the direction of its flow – the tails of South America and the Antarctic Peninsula just out as irritations but the ocean is connected, west to east. This means that waves have time to build and build as they travel around the bottom of the Southern Hemisphere. One narrow slither of land, Sub-Antarctic Macquarie Island, only 34km long, suffered the consequences of its placement of its location last week when a storm of extraordinary magnitude hit. Out as sea were waves around 17m high; waves the size of a 5 story building, or a humpback whale standing on its tail.
While the island at its maximum is 5km wide, at its minimum, it’s only a few hundred metres. This narrow isthmus is the location of the Antarctic station and also where, at this time of year, elephant seal harems are assembled with new pups arriving most days.
The storm crashed across the isthmus and into the harems. Seals scrambled for slightly higher ground but many, including the big males were washed away by the pounding seas. Post-storm population counts indicate that, most have survived, (who would have thought, seals can swim) but pandemonium descended for some time, when pups were separated from mums.
Unsurprisingly waves ignored the station fences built as deterrents to seals seeking peace from the chaos of the harems and angry beachmasters patrolling their patch. The station’s main store was flooded and water washed through the central courtyard known affectionately as Market Square from the west coast to the east. (see image from a drier time )
Details and photos of the storm can be found at “This week at Macquarie Island“.
Climate change predictions are for more extreme events and more storm events world-wide. This storm illustrates impacts of pounding seas to low lying features and human settlements. It also illustrates that timing of exteme events can have long-term impacts. Though the counts say that seal numbers are ok, there inevitably would have been the loss of some very young seal pups and this dent in population numbers will carry through for the next 25 years or so.