Cavan County Council has reported "severe flooding" throughout the Ballyjamesduff Municipal District area this morning.
Crews are out investigating while extreme caution is advised.
Elsewhere, power cuts have been reported in Wicklow, Wexford, Kerry and Cork, as southern counties deal with a status orange rain warning.
The four counties along with Waterford will experience thundery downpours and spot flooding until midnight.
Eleven other counties have a yellow rain alert in place, including Limerick and Tipperary where significant power outages have been reported.