Cyclone Seth Splits Bribie Island, New Channel Permanent
In 1898, a storm event overtopped a narrow isthmus on Stradbroke Island and split the barrier island into two halves. The combined efforts of waves and tidal flow saw the channel grow and become a permanent bar - the infamous Jumpinpin - while South Stradbroke and North Stradbroke became distinct islands.
Earlier this month, another of south-east Queensland’s barrier islands was split and scientists believe the result will, like Stradbroke, be permanent.
On the 2nd January, with swell from Tropical Cyclone Seth battering the ocean side, and an associated deluge raising water levels in Pumicestone Passage, Bribie Island was split, with waves breaking through a narrow spit at the northern end.
Aerial photographs show the extent of the breach.
Northern Bribie Island has a long history of shifting sands. In the early 1970’s the entrance to Pumicestone Passage was well south of its present location at Caloundra and just north of the new entrance position (see image below).
More recently, waves overtopped and eroded the island in December 2020, however it wasn’t enough for a channel to form.
On January 4th, the Principal Scientist from Queensland’s Department of Environment and Science (DES) visited the site, observing the newly formed tidal channel. The formation of said channel leads the DES to believe that this will become the new northern entrance to Pumicestone Passage and that Caloundra Bar will slowly fill with sand.
Surfers will greet the news with mixed emotions as, though fickle, Caloundra Bar offers respite from northerly winds. No longer will the banks there be groomed by tidal flow. Conversely, the new channel, though more exposed to wind, is showing promise with a left and right on each side.
Locals will soon get a look at those waves, as starting tomorrow a fresh round of easterly swell from TC Cody will hit the coast, and like the last swell it will be a sustained event lasting till this time next week. The DES said it’s “not possible to speculate on whether any further washovers or breakthroughs will occur in nearby sections of the island”.
As the new channel is a naturally occurring event there are no planned remedial actions.