Wales braced for River Severn's 34ft 'super-tide'.
Byline: Darren Devine Reporter firstname.lastname@example.org
THE biggest high tides witnessed for 25 years could sweep the Welsh coast this morning amid warnings of flooding on roads and spray on piers and promenades.
Experts said the "super-tide" would hit at 8.51am, with the surge six to eight inches higher than normal.
Natural Resources Wales (NRW) say it could be greater still if combined with rough weather. And a Met Office spokesman said gales from mid-morning tomorrow and into Monday are likely to make later tides even higher.
Spokesman Greg Dewhurst predicted winds of 40mph to 45mph. He said: "With those sort of wind strengths they will have an effect on the tidal range.
"They will make the waves bigger. It depends if they exactly coincide with the higher peaks of the tide, whether or not they will cause an addition to the higher tides.
"But I imagine looking at the strength of the winds there will be some influence from the wind on the tides."
The high tides are likely to affect most of the coastline, but the stretch along South Wales - from Gower through to the Wye Estuary - is likely to be most affected.
A rare planetary alignment means Wales and the rest of Britain could face a year of super-tides and potential flooding along vast swathes of coastline, scientists have warned.
Tides are governed by the gravitational pull of the moon and, to a lesser extent, the sun.
When the gravitational pull of the sun and moon combine, we see larger-than-average tides - known as spring tides.
But we can also see additional, small increases linked to the gravitational pull of the planets in our solar system.
It's expected intrepid surfers will take to the water hoping to make the most of a thrilling Severn Bore.
The rare "five-star" bore will see a wave of water surge up the Severn Estuary for more than 20 miles.
The tide is set to rise to 10.4m (34ft) - the highest it is likely to get this year.
But floodwater coming downstream could reduce the wave's power.
At a similar time last year around 30 surfers rode the wave. Thousands of people turned up to witness the tidal phenomenon, which is caused when rising tides are funnelled up the estuary.
The Severn Bore is one of eight such phenomena to occur in the UK, and the Severn Estuary has the second largest tidal range in the world.
At spring tides the Severn Bore can reach a height of up to 25ft (7.5 metres) and a speed of 17mph.
Last night NRW issued two flood warnings and six flood alerts. The warnings are in place for the Wye Estuary at Chepstow and Tintern, There were alerts in place along the Welsh coast from North Wales, to Ceredigion, Pembrokeshire, Carmarthenshire, Swansea, Aberthaw to the Severn Bridge and the Usk Estuary.
A warning means flooding is expected and immediate action needed. An alert means flooding is possible and you should be prepared. NRW is also advising extra care near the coast this weekend as the tides could be dangerous.
Surfers ride a rare five-star Severn Bore, <Bviewed from Minsterworth on the Severn yesterday Matthew Horwood