Tens of thousands of homes and businesses are without power in the Shannonside Region as storm winds batter the country.
Red wind warnings have come into effect in two counties in the north-west, as Storm Isha makes landfall.
Met Éireann says the storm is tracking to the north-west and won't cross the country, but will still cause severe disruption.
Delays are expected to train services as speed restrictions are in place for western services.
A tornado watch has also been issued for Ireland, with potential for funnel clouds to develop during thunderstorms.
Met Éireann's Liz Walsh says tornadoes are a possibility.