Ireland's national weather service says the country has seen 114 mph wind gusts, the highest ever recorded on the island.
A red weather warning is in place for Scotland, where a "once in a generation storm" is causing widespread disruption.
Ireland has been hit with record wind gusts of 114 miles (183 kilometers) an hour as a winter storm batters the country and northern parts of the U.K. Schools have been closed, trains halted and hundreds of flights canceled in the Republic of Ireland,
ESB Networks in Ireland and NIE Networks say they expect significant further outages as Storm Eowyn continues to batter parts of the island.
Clean-up operations are anticipated to take days and possibly even weeks in some parts of Northern Ireland, with Storm Éowyn bringing gusts of over 90mph across some parts of the region.
A red wind warning has been issued for the whole of the Republic of Ireland, with Met Éireann warning of a possible "danger to life". The alert comes into effect at varying times from 02:00 on Friday and will end at varying times. Met Éireann has warned that "severe, damaging and destructive winds" are expected, with gusts of up to 130km/h.
There are warnings of danger to life, fallen electric lines, damaged infrastructure and widespread power outages
More than 93,000 homes and business in Northern Ireland are currently without power, NIE has confirmed. Dozens of flights have also been cancelled at Belfast airports this morning as high winds from Storm Éowyn begin to batter Northern Ireland.
A powerful storm has left hundreds of thousands of homes without power and caused massive travel disruptions in the United Kingdom.
The storm had knocked out power to more than half a million utility customers by early Friday as it moved across Ireland.
Both Northern Ireland and the Republic of Ireland are under the top-level red weather warnings for wind from early on Friday.
More than a million homes and businesses without power across island of Ireland - ESB Networks in Ireland and NIE Networks say they expect significant further outages as Storm Eowyn continues to batter parts of the island.