Stuart Thompson, from the RNLI, says one of the risks of tombstoning is the sheer unpredictability of the environment.
"The problem is that you know heights of tides change, conditions change" he says.
"The conditions of the seabed change as well so it's actually quite a dangerous practice".
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It should continue to become drier and brighter from the west. However, a sharp shower is possible.
The heaviest bursts are expected in the south and east, with some western areas either remaining dry or becoming dry by dawn.