A service is underway at St Asaph Cathedral in memory of 91-year-old Margaret Hughes, who died during last week's floods.
The Dean of St Asaph said prayers and reflections will take place in the theme of 'Light in our Darkness'.
The service is also intended to provide hope and comfort to residents, many of whom face being homeless for Christmas.
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An inquest is to be held into the deaths of four family members who died when their car was involved in a crash near Aberystwyth in June.
Cold and windy with sunny spells and showers of rain and snow.
The charity says the increase is partly due to people calling for help sooner, instead of attempting to rescue themselves.