Winds of up to 122 km/h have been recorded just off the coast of Cork today.
The strongest gusts from Storm Diana hit Sherkin Island according to Met Eireann.
Meanwhile, Casement in Dublin recorded high winds of 115 km/h.
Latest rainfall radar, 12pm to 1pm.
Highest gusts so far today (km/h):
— Met Éireann (@MetEireann) November 28, 2018
Up to 40,000 homes and businesses were without power at one point this morning.
Paul Hand from the ESB says crews are now deployed to the worst hit areas.
He says crews are working throughout the afternoon to restore power where it's safe to do so.
Storm Diana is expected to clear Ireland by 6pm this evening.