An investigation has been launched at Letterkenny General Hospital in Co Donegal which has been hit by flooding for the second time in less than a year.
Its emergency department was offline for three hours, just 12 months after €25m in damage was caused in a similar flood.
Emergency crews rushed to the scene at the hospital from 7pm last night when over 40 milimetres of rain fell in just 15 minutes.
Floodwaters breaching defences forcing the emergency department to be closed.
Patients were asked to divert to Altnagelvin Hospital in Derry or Sligo Hospital while emergency crews pumped water away from clinical areas until just before midnight.
Hospital management say an investigation into the cause of the flooding has been launched, but local politicians say that is not good enough.