Almost 500 homes, farms and businesses in the Shannonside region remain without power this lunchtime after thunderstorms overnight.
West Roscommon is particularly badly affected, with significant outages in Ballaghaderreen, Lisacul and Carrowbehy.
Mohill in Co Leitrim was also one of the worst areas impacted, but power has now been restored to all but 66 premises there.
The ESB is working to restore power to all homes by this evening.
Cathal Nolan from Ireland's Weather Channel says last night's conditions won't be repeated soon.