Storm Ophelia: record 26m wave at Kinsale gas platform off south coast

Individual wave a metre higher than Storm Darwin wave at energy rig in 2014

Storm Ophelia may have set a wave height record in Irish waters, with a wave of just over 26m recorded at the Kinsale gas platform off the Cork coast.

The 26.1m high wave that broke over the platform on Monday during Storm Ophelia beats the previous 25m wave record set at the platform during Storm Darwin in 2014.

Staff were on duty at the platform run by Kinsale Energy, formerly Marathon, throughout the tropical revolving storm which swept up over the south coast early on October 16th.

It evolved from the strongest eastern Atlantic hurricane in 150 years of records, according to University College Cork climatologist Dr Kieran Hickey.

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The Marine Institute’s M5 weather buoy recorded an individual wave height of almost 18m before it broke its moorings off the southeast.

The M5 buoy also recorded a significant wave height of 12.97m.

A significant wave height is derived from the average of the highest one-third of waves measures from trough to crest in a given period.

Northwards

As Ophelia moved northwards, the M2 buoy to the east of Dublin also experienced a record significant wave height of 6.64m measured at 18.00 on Monday, October 16th, the institute said.

Earlier in the day, at 12.00, the M3 buoy off the southwest coast measured an individual wave height of 13.59m, although this was not a record wave for this buoy, it says.

Dr Hickey said that the top gust of 191km/h recorded during Ophelia at Fastnet lighthouse off the southwest coast was at 200ft or almost 70m, and not at the standard 10m that would make it comparable to other recordings.

Ophelia had sustained winds (10-minute mean) of 111km/h at Roches Point, off Cork, and gusts of up to 156km/h on land.

Three people died in the Republic during Ophelia, compared to four – and possibly six – during the subzero temperatures of December 2010. There were 18 fatalities on the island of Ireland during Storm Debbie in 1961 and 11 died when Storm Charley hit Ireland and Britain in 1986.

‘Big wind’

Dr Hickey, who is head of UCC’s department of geography, said Ophelia had one factor in common with the “Big Wind” of 1839, which caused hundreds of deaths, as it affected the entire island.

“We can say that Ophelia was the strongest eastern Atlantic hurricane on records – dating back to the mid-1800s – as a category three hurricane,” Dr Hickey said.

The tropical revolving storm occurred during the seventh most intense Atlantic hurricane season since 1850, with 10 hurricanes in 10 weeks so far.

This is the only time 10 hurricanes have been recorded in a single season in the satellite era, he said, but could be comparable to 1878, 1886 and 1893 when there could have been a few more that were not recorded.

Recent hurricanes have recorded 357 deaths and an estimated $186.8 billion in damages internationally so far, according to data recorded before Ophelia hit Ireland as a tropical revolving storm, he said.

The ESB has said that Ophelia caused the largest extent of cuts to customers in its history, with the Cork coast being worst hit.

Lorna Siggins

Lorna Siggins

Lorna Siggins is the former western and marine correspondent of The Irish Times