Sudden lightning storms hit the country yesterday, leaving 20,000 homes and businesses without electricity and creating major problems for the ESB.
The company described the lightning as the worst in recent history and said the problems were compounded because there were so many "separate incidences" as the lightning played havoc, randomly, with trip lines all over the country, putting pressure on manpower resources.
Storm damage usually meant repairing centralised faults, an ESB spokesman said, but damage caused by lightning tended to be much more diffused and so more people were needed on the ground to identify and reset trip wires.
"Lightning uses vast amounts of energy," the spokesman said. "Each hit is equivalent to one billion volts of electricity for every single strike. This has severe consequences for local systems on the ground, which just cannot cope with this sort of impact."
The lightning protection built into local systems cannot withstand this level of energy, he emphasised. And it could take from two to three hours to fix each "damage occurrence" so the ESB expected its manpower to be fully stretched through the night.
The worst-hit areas were around Bandon and Dunmanway in Co Cork when the thunder storms first hit the coast at around 9 a.m.
Telephone services in that area were also badly affected, with 400 Eircom customers in Co Cork, from Bandon to Clonakilty and Macroom to the north, left without landlines.
The thundery rain and showers moved up from the south and quickly spread across the country. Initial reports showed the worst-affected areas after Cork to be Roscrea and Nenagh in Tipperary, Carlow town and Blessington in Co Wicklow, as well as north Dublin.
Telephone lines were also badly hit in Co Limerick, leaving 400 customers without phones due to the lightning, Eircom reported.
Eircell fared better with mobile phones, despite some early difficulties in the Munster area because of problems with a back-up power supply system.
While the winds at ground level were north-easterly in direction, the breezes that brought the thunder storms to the south coast were at 10,000 and even 20,000 feet and Eireann - they were southerly or south-easterly in direction. The winds travelled up from the Bay of Biscay during the night and hit the south coast before spreading north across the country. The result was the thundery rain and showers that Ireland experienced for much of the day.
Some heavy mist and fog was experienced last night, with some rain in the north and east of the country. Sporadic thundery bursts were expected to continue until early morning, with an improvement in conditions, heralded by fresher winds from the Atlantic, spreading across the country by this afternoon.
In general the weather will be brighter and fresher today, with a few isolated showers in some places. Temperatures will be lower - in the high teens, as distinct from the low to medium 20s that the country has been experiencing in recent weeks.
Tomorrow will generally be a bright, fresh day with some showers, according to Met Eireann. It will not be as warm as in previous days, but lower humidity with less likelihood of thunder will be a bonus.