Ophelia leaves thousands of Irish homes and businesses without power
The Met Office has warned of "potential danger to life", with winds off the south coast of Ireland reaching 109mph (176km/h) at Fastnet Rock.
A very busy Tesco in Belfast as people stock up before the storm
Schools in Ireland have been closed and and some public transport suspended and the army has been deployed to coastal counties.
There are now 100,000 homes and businesses hit with power cuts as lines are knocked down, according to the Electricity Supply Board in the Irish Republic.
Ophelia is on its way from the Azores in the Atlantic Ocean and it comes 30 years after the UK's Great Storm of 1987.