Low Risk; Less than 1 in 100 (1%) for rivers and surface water flooding and 1 in 200 (0.5 per cent) for the sea but greater than or equal to 1 in 1,000 (0.1%) chance in any given year.
Risg isel; Bygythiad llai nag 1 mewn 100 (1%) ar gyfer afonydd a llifogydd dŵr wyneb ac 1 mewn 200 (0.5%) ar gyfer y môr ond yn fwy na neu'n hafal i 1 mewn 1,000 (0.1%) mewn unrhyw flwyddyn benodol.