The River Moyola in County Derry was flooded this week.
People are being warned to expect more stormy weather this weekend.
Storm Dennis will bring 'very strong winds' and potential for transport disruption from Sunday, the Met Office said.
A yellow wind warning is in place from midday on Sunday ending at midday Monday.
The Met Office said: "Storm Dennis has the potential to bring very strong winds and transport disruption during Sunday and Monday morning.
"Wet and very windy on Saturday. Sunshine, blustery showers on Sunday, gales or severe gales."
There has been localised flooding in various parts of County Derry this week.
However, the Met Office said that Storm Dennis is not expected to be as severe as Storm Ciara.
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