Mystery surrounds a strange tidal incident in West Cork on Saturday that saw at least two harbours almost drained and refilled in quick succession.
Many in Union Hall and Courtmacsherry said they'd never seen anything like it as videos show tides rush out leaving vessels in the mud, before surging back in again very quickly.
The surges went on for at least an hour-and-a-half, and there's a number of unconfirmed theories as to what may have caused it.
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Some have speculated there may have been a distant offshore earthquake or submarine landslide leading to a small tsunami. There was a small one (magnitude 2.7) reported off Portugal at San Jorge Island at 8.32am on Saturday morning.
Others suggest it could be a combination of atmospheric pressure and a northerly wind at the time, although locals have dismissed the idea as they say it it would be a more regular occurrence if that were the case.
Adrian Nowotynki of Irish Deep Sea Charters was coming into Union Hall as it started happening around 3.40pm, and described the whole things as a bit "nuts".
He said: "I'd just come back in and it was a fairly calm and normal day. I was ready to get off the boat and I noticed them all swinging around.
"My boat would barely touch the mud at the lowest of tides but it dropped well below.
"The tide came back in about a metre higher suddenly and broke its way across the mudflats. I rowed over to another boat then it started flowing back out again in the space of a few minutes.
"I watched at the bridge in Union Hall until around 5pm and saw it come in and out about five times.
"Each was a little less than the previous.
"There's parts of the bay that dried out, I'd never seen them like that before. One of the fishermen in the harbour heard the noise of it from his house and came out to see it all happen.
"I didn't see any damage.
"The tide in Union Hall would be like a wide river when it starts going out usually, but this all happened when the water level was low so there should've have been any tide at all.
"Nobody's ever seen it go so low and it's never been like that on a normal astronomical tide either.
"We think there was either some sort of event relating to pressure or wind or maybe an offshore earthquake that caused some sort of tsunami.
"It came in like a tidal bore but that doesn't happen in Union Hall.
"We've made some calls but as of yet we're still not sure. All we know is that there were similar incidents reported in the channel and on beaches in Wales too.
"I've never seen anything like it."
As Adrian recorded, over in Courtmacsherrry there was a similar scene, with West Cork Charters saying harbours along the south coast had "emptied out like never before".
They wrote: "Looked like an earthquake off the coast today, harbours along the south coast emptied out like never before. Then started filling again."
CorkBeo has contacted Ireland's Marine Institute and the British Geological Survey to see if they can shed any light on what caused it.