An elderly lady has been found dead, and hundreds of others were forced out of where they live and work, as water swept through St Asaph in Denbighshire early on Tuesday morning.
North Wales Police says 500 homes were evacuated, after the River Elwy burst its banks. Many had to be rescued by lifeboats, as they were trapped in their homes by rising water. More than 100 found shelter in a leisure centre in the city, receiving hot drinks and blankets, with help from the British Red Cross.
Nearby, several villages south of St Asaph were cut off for much of the day. In Ruthin, around 300 people on a brand new housing estate were forced out of their homes - many angrily remembering assurances they would be safe from flooding - and told about the water rushing into their communities only by the local postman.
Carl Edwards has the story of a day of devastation in North Wales.