More than 100 people had to be rescued in Northern Ireland after being trapped by overnight flooding.
The north west was worst affected, particularly Londonderry, as well as other parts of the county and Tyrone.
Firefighters rescued 93 people who were trapped by flood water in their cars or homes. At one point, the fire service got an emergency call every 45 seconds.
The Met Office confirmed that 63% of the average August rainfall fell within an eight-to-nine-hour period.
The coastguard rescued more than 30 people, with helicopters brought in from Scotland, Wales and Sligo.
DUP leader Arlene Foster travelled to Drumahoe in Londonderry to meet victims.
Sinn Féin's northern leader Michelle O'Neill said the process of rebuilding would require a "robust and concerted approach across several different government departments."
"Clearly questions need to be answered about the state of preparedness and the response of some statutory agencies," she added.
Dawn Grieve and her two young sons were rescued from their home in the Ivy Mead area of Derry by tractor.
"I had to leave the house, I actually got a tractor ride out of there by two local boys - their mum lives at the top of our street," she said.
"I have two young boys, one is four and one is two, and we had to get out of there at about half three this morning.
"It was too bad for them - they were scared."
The ambulance service said it responded to 10 calls directly related to the weather, including one case of hypothermia.
Other people were helped by the police.
Brigid Mullan, from Claudy, told BBC News NI she was stranded on the Victoria Road in Derry.
"We met a woman from Plumbridge who was very, very distressed so I offered to try to get her to Plumbridge.
"We didn't get near Plumbridge, we got halfway there and the roads were flooded. We had to turn."
Bridges collapsed on the Camlough Road near Carrickmore, County Tyrone, and on Church Steet in Claudy, County Londonderry.
Paul Duddy, a motorist caught up in the flooding, told BBC News NI he had "never seen anything like this in all my life".
"It was terrifying, particularly whenever I saw the water coming up over the bonnet of the car. I don't know how the car didn't stall completely."
"Firefighters worked in extremely challenging circumstances to reach people," Alan Walmsley of the fire service said.
"A number of roads were impassable due to flooding and crews had to take alternative routes to attend some incidents."
The Department for Infrastructure said a "multi-agency conference meeting" was held on Wednesday.
In a statement, the department said the Red Cross and the Western trust had assisted in temporary accommodation centres overnight.
"The scheme of emergency financial assistance, which is administered by councils is open to all residents significantly affected by flooding within their homes," they said.
The Foyle Arena was opened from 23:00 BST for those affected.
Ryan Gray, from the Coastguard, said: "Flood water up to 6cms in depth will take a human being off their feet and if it does so, it's very unlikely that the person will be able to stand up again."
"This was a metre and a half of flood water - it was lifting vehicles up and taking them down, the current of the water.
"There was a little bit of panic, thankfully the rescue teams are very well trained and they managed to calm the scene down and rescue people."
Shocking flooding tonight. Families and businesses struggling to cope and big questions for statutory agencies. Where was the preparation?— Colum Eastwood (@columeastwood) August 22, 2017
SDLP leader and Foyle MLA Colum Eastwood tweeted that the flooding was "shocking".
"Families and businesses struggling to cope and big questions for statutory agencies. Where was the preparation?"
The Roads Service say a number of roads remain closed on Wednesday.
It is understood that about 600 Northern Ireland Electricity customers are still without power.
Derry City and Strabane District Council remained open until 22:00 BST on Wednesday and will reopen from 08:00 on Thursday to provide support and assistance to those affected.
Translink has said there would be severe disruption. Full details are on the Translink website.