Met Office says parts of Northern Ireland had almost one month's rain in 24 hours after Yellow Weather warning
Parts of Co Down saw almost a full month's rain falling in 24 hours - causing flash flooding and difficult driving conditions in several places, the Met Office has reported.
The heavy rain came after a prolonged hot spell across Northern Ireland, with the Met Office issuing a yellow-level rain warning for Counties Antrim, Armagh and Down from 6pm on Sunday to 6pm on Monday.
The forecasters had warned that there was a risk that homes and businesses could be flooded.
It also cautioned that some communities could be cut off by flooded roads while fast-flowing or deep floodwater could pose a danger to life.
Some 70 visitors to the underground tourist attraction, the Marble Arch Caves in Enniskillen had to be evacuated on Sunday evening as the heavy downpour caused water to flow down stairs and stairwells into the complex at an alarming rate.
NI normally records an average of 89mm of rain in July but falls of between 50-75mm had been predicted over a period of just 12 to 18 hours.
"Since 6pm on Sunday Killowen in Co Down recorded 71.8mm of rain, with Murlough in Co Down recording 61.8mm," a Met Office spokesman told the News Letter.
"The July average for Killowen is 80.75mm so just shy of a months’ worth of rain has fallen since yesterday [Sunday] evening there. The July average for Murlough is 68.96mm so again just shy of a month’s rain has fallen there too."
"County Down certainly recorded the wettest conditions - with our site in Thomastown in County Fermanagh recording only 12mm by comparison in the same period."
Speaking at 4:45pm on Monday, the forecaster said the rain was starting to ease so the totals may rise a little more, but that the main bulk of the rain had passed.
Police said the M12 off the M1 at Portadown was closed for much of Monday as a result of the heavy rain.
The country bound lane was impassable at Portadown (junction 12) due to heavy rainfall, and police asked motorists to come off the motorway at junction 10.
It reopened again about 3:45pm
On Sunday night police advised drivers that the Marble Arch Road, Florencecourt and Sligo Road, Enniskillen were both impassable due to floods.
Police also said flooding was affecting other parts of west Fermanagh.
There were also reports that the main Enniskillen to Dublin Road in Enniskillen, County Fermanagh suffered flooding.
The Blacks Road underpass in west Belfast was also difficult to pass due to high levels of standing water.
In Fermanagh, a woman who was visiting the Marble Arch Caves said the quick thinking and professionalism of staff at Marble Arch Caves kept them safe during the evacuation.
Kim Hay said that because the Marble Arch Caves guides were so calm, “fast-thinking” and had a plan, they did not panic.
“The team was amazing, I don’t think at any point that we feared for our lives,” Mrs Hay told PA.
Today the caves are closed for a major clean up operation, as staff clear sediment and sand from paths and stairs in the complex.
It is understood the caves are due to open again on Thursday morning.
Kim said that two children on the tour were a bit frightened, but their parents and guides assured them that they were safe.
“We were speaking to the manager, she came and talked to us after and she reassured everyone that in her 20 years of working there, she had never seen anything like that before. “It was quite the experience.”
She added: “I think it was definitely one of those things where you can just look back and be very thankful that everybody got out safe, nobody was injured.
“On reflection, I think the more we watch the video ourselves, the more we realise it could have went horribly wrong, except for the fast, quick action of the staff getting everybody out to safety.”
Since 6pm on Sunday Killowen in Co Down recorded 71.8mm of rain against a July average of 80.75mm, the Met Office said late yesterday afternoon.
The country-bound lane of the M12 road off the M1 at Portadown was closed most of yesterday due to flooding.
On Sunday night the Marble Arch Road, Florencecourt and Sligo Road, Enniskillen were both impassable. The Blacks Road underpass in west Belfast was also difficult to pass yesterday due to high water.