Data from the M3 and M5 buoys off the South Coast is being recovered for analysis by the Marine Institute to ascertain whether it can explain the cause of a tidal drop of 70 cms reported at Union Hall and Courtmacsherry in West Cork last Saturday afternoon.
Local people described the tide level dropping in a few minutes and then flooding back in.
There have been further reports of similar happenings on the Wexford coast and in Wales.
As Afloat reported earlier, descriptions of what happened in the area of Glandore Harbour where Union Hall is located have varied, from some people describing water levels leaving boats temporarily touching bottom where they were moored, to others who claimed the tide “came in and out several times…” and another comment: “the tide was going the wrong way…”
A fishing boat in Glandore Harbour
Amongst reports of seismological activity on Saturday were a 2.6 magnitude earthquake before noon near the Azores. That was logged at the European Mediterranean Seismological Centre.
Historical context records a 1755 earthquake off the coast of Portugal, which was reported to have caused damage on the Irish South Western coast.
Amongst suggestions for the cause is atmospheric pressure, northerly wind and known water actions at the areas involved. Oceanography sources have tended to discount the incidents in West Cork being associated with the seismic action off Portugal. “It would not be big enough to have that effect,” I was told. “Rare, unusual, possibly driven by a number of factors that may lead to an unusual event, but in this case the cause is so far not clear, so examining date from the buoys at sea may help to indicate it.”
No other Cork coastal areas have reported anything similar.
A Marine Institute statement said: "An unusual tidal event was observed on Saturday 18th June 2022 at Union Hall (West Cork) at 14.40 (UTC) with a low water of -2.629m measured by the Irish Tide Gauge Network.”
