Dublin airport has reopened this evening after being closed for several hours because of heavy snowfall.
Passengers face long delays after 183 arriving and departing flights were cancelled.
Snow clearance work and tests on the airport's main runway were carried out this afternoon. A spokeswoman for the Dublin Airport Authority said favourable weather conditions had resulted in good progress being made on the main runway, apron and taxiway areas.
The authority decided to reopen the main runway this evening. It said priority would be given initially to departing flights.
The main runway was closed at 12.50pm. All flights due to land at that time were diverted. The spokeswoman said the runway was closed because the snow was falling faster than they could clear it.
"When the snow is falling heavier than it can be cleared, there's just no point," she said.
The authoity has advised intending passengers to contact their airline before travelling to the airport.
Ryanair and Aer Lingus were both forced to cancel flights in and out of Dublin this afternoon, with some knock-on effect on flights to or from other European airports.
Aer Lingus said earlier it had decided to cancel all flights for the rest of the day, with the exception of flights EI184 from Dublin to London Heathrow and EI109 from Dublin to New YorkJFK. The airline said it plans to operate a full schedule of flights tomorrow.
Passengers with tickets for the cancelled flights may re-book at no additional charge on the Aer Lingus website, or by telephone at 01 886 8383 from Ireland or 00 353 1 886 8383 from Britain. A spokeswoman said passengers choosing not to travel could obtain a refund.
Ryanair was also forced to cancel more than 70 flights to and from Britain, and to other European airports.
It published details on its website. The company said customers booked to travel on one of the cancelled flights may re-book their flights free of charge and subject to availability. Passengers may also travel to their booked destination by transferring their flight to travel from or via another airport.
The airline also set up a 'flight disruption' line to provide information to passengers. The number is 353 1 2480857 for Ireland and for outside Ireland.