Thousands of people were left without power in Kerry, the first county to be hit by the storm called after its native saint, Brendan on Monday morning.
Dozens of trees were brought down.
At one point 10,000 customers had no electricity, but most were expected to be restored by Monday night with council and ESB crews battling hail and heavy rain to clear roads and fix power lines.
South Kerry was one of the worst affected early on Monday with practically every house in Cahersiveen and Waterville left without power.
However most of the county’s 700 kms of coastline was affected with power and communications lines brought down.
At one point up to fifteen trees lay across roads, with Kenmare and Lauragh and the Beara Peninsula badly affected.
Mid morning, the Killarney National Park including Muckross House and Killarney House announced it had closed its gates to the public, advising walkers to stay away from the park with its thousands of trees.
The storm in Kerry peaked at 11am with lashing rain and hail storms on higher ground.
The early morning Kerry to Dublin flight was cancelled and a number of scheduled events in Tralee were postponed.