A metronome to coastal life, the tides can completely transform a landscape in a matter of hours, as vast expanses of sand are hidden beneath the waves. Taking in giant waves, funneling effects, mermaids purses and beach safety, lifeguard, surfer and writer Pete Geall is our guide to the tides…
‘Waiting for the push’ is a phrase you might hear repeated around Watergate Bay. If you look closely, you’ll see them patiently waiting. Up in the lay-by that overlooks Towan headland across to the wilds of Park Head in the north. Down in the car park nestled in the shelter of the valley. Surfers will invariably be ‘waiting for the push’ before slipping into their wetsuits. Some will be openly sharing their plans, others whispering more furtively.
Much vaunted surf parlance, ‘the push’ describes the ability of an incoming tide to increase the height of the waves. In the summer months, when the surf is frequently small, this twice daily event can mean the difference between an average surf session and a superlative one.
But it’s not only surfers who take note; the tides shape all beach life at Watergate – a metronome to the comings and goings on the sand. In many ways coastal life here is defined by the small, physical reminders of time that add up into a sum of their parts. The ebb and flow of the tides; the clatter of shutters as the Shop on the Beach opens for the day; the die-cut path of the sun towards the horizon line; and the lifeguards cheerily clocking off at 6pm.
Watergate has many moods, the wild winter scenes no less beautiful than the placid calm of a summer’s day. Finding solace in that change is part of the Bay’s appeal. While it’s true that “time and tide wait for no man” (anon), there is a reassuring consistency to its perpetual movement. A fluidity that belies its true power.
The ever-changing tide gives the Bay two distinct personalities. On large low tides the two-mile long stretch of sand opens into an impressive expansiveness that makes it easy to find space and solitude, even on the busiest of summers days. Conversely, on a high tide the Bay gains a new intimacy, as the water meets the sea wall – the position of which provides the perfect spot for a sundowner perched just above the Atlantic wash.
I must go down to the seas again, for the call of the running tide Is a wild call and a clear call that may not be denied.
John Masefield – ‘Sea Fever’ (1902)
Most of us are well aware of the tide’s effects and seemingly unending appetite to get our beach belongings wet. But what exactly causes the tide?
At its simplest, the tide is the vertical motion of water. When viewed in a deep harbour, water will appear to move up and down this vertical plane at a speed imperceptible by eye.
As the earth rotates on its axis, the changing gravitational pull from the moon causes two giant waves to flow around the planet. When the peak of this wave passes our shores it is high tide and when the trough passes, it is low. It takes around 6 hours and 12.5 minutes between the trough and the peak. This is the time between the low and high tides.
In Britain, where we have a semi-diurnal tide cycle (when the two highs and the two lows are about the same height), the key timings are: 6 hours 12.5 minutes between high and low tides, 12 hours and 25 minutes between high and high, and 24 hours and 50 minutes for a full cycle. Phew, take a breath.
Although these timings are consistent, it doesn’t take into account the presence of land on the movement of these two tidal bulges travelling around the planet. Coastlines and irregular seabeds can break up the journey of these tide waves, causing the tides to be amplified by certain topographic features – for example, the funnelling effect of the Bristol channel, which has some of the largest tidal ranges in the world, with over 14 metres between low and high water. Here on the North Cornish coast, the average tidal range is a more modest 6 metres. Considering this figure represents the vertical change in water height (between the lowest and highest point of the tide’s cycle), it helps explain why the tide at Watergate travels such a large distance over the gently sloping beach.
Reconnecting with the coast and tide is a great way to untether yourself from the constant barrage of notifications of modern life. Observing and discovering the many tidal indicators can open up an extra dimension to your understanding of the beach environment.
If you find yourself on a new beach or unfamiliar coastline without a way of accessing the tide times for the day, what are the tell-tale clues of the current tidal state?
The high tide line on a beach is often clearly visible as a line of seaweed, sea creatures and assorted flotsam and jetsam. Exploring the ‘strand-line’ can yield unexpected finds. Look out for a ‘Mermaids Purse’ (the egg-cases of different species of shark) or take part in an impromptu beach clean.
A walk along this distinct line is the best way to approach beach-combing or a beach clean. If you find any branded plastic waste, why not participate in environmental charity Surfers Against Sewage’s plastic pollution campaign #ReturnToOffender – take a photo of your find and share on social media tagging the offending manufacturer and using #ReturnToOffender #SurfersAgainstSewage.
Storms and springs
If you look above the current tide line you might find larger items – fishing buoys, large logs and even the odd telegraph pole – either washed up by a past storm event or by larger ‘spring’ tides. These occur every month (not just spring), when the gravitational pull of the sun coincides with the moon to cause especially large tides.
Generally the further you travel up a beach away from the water, the sand texture will become coarser. On smaller ‘neap’ tides, the central part of the beach at Watergate won’t get covered by high tide. As a result it has a drier, ‘powdery’ appearance caused by the shuffling feet of beachgoers. If you plan on spending a day on the beach, take note of this zone – it’s the ideal place to set up without worrying about getting caught out by the incoming tide.
On a dry day, wet sand that is free of footprints below the tide line is a good indicator that the tide is dropping. As a full tide cycle takes 24 hours and 50 minutes, if you know the tide time of a day in the previous week, you can easily work out the approximate time of the tide by adding an hour to that time for each day that has passed.
Understanding both the cause of the tide and the clues of its current phase are key to staying safe at the coast. But even with this knowledge, it’s easy to get caught out. To stay safe