Parts of County Fermanagh were flooded last week
People have been warned to take particular care when they go out in flooded areas as water levels in Lough Erne continue to rise.
Director of the Rivers Agency in the west, David Porter, said flood waters could put people in "grave danger".
More floods are expected in County Fermanagh as heavy rain continues to raise water levels.
"The volume of water means that in certain places in the river network the water is travelling very fast."
"It may not look on the surface as if it is but there are underlying currents, and if you got into those in certain areas you would be in grave danger.
"The other thing about flood water is that it hides many of the hazards that are underneath it, so if you're walking through it a dislodged manhole is very hard to see," he said.
Several roads were closed last week as Lough Erne rose to record levels.
Vehicles are being diverted through Enniskillen, as it is the only passable route from the east side of the lough to the west, and delays are expected.
Riverside pathways in Enniskillen are well under water and car parks at Wellington Road and Broadmeadow are also badly affected.
A Roads Service spokeswoman said: "Motorists should not risk driving through floods unless you are sure your vehicle can cope with deep water."