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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Wales head coach Rob Howley admitted his side's performance 'simply wasn't good enough' against Scotland this afternoon.
It will be cloudy with outbreaks of rain at first, but most of the rain will clear by morning.
Despite leading at half time, Howley's men failed to score in the second half with Scotland racking up 20 points to seal the win.