Sunday, 15 July 2012

Water safety ~ check those swells and surges!

Snow on the deck!
It was early in June and a cold, clear morning.  No wonder it was cold: there was a dusting of snow on the deck!  A few days before Rewi had checked the tide and decided it would be a good day to go musselling: the tide was expected to be especially low (.4 of a metre), but it was so cold it seemed daft even to consider it.  However, Rewi was adamant.  Such low tides occur only for a few days each month and reveal certain parts of the beach which are not otherwise accessible and he was determined to take advantage of it.

I reluctantly agreed to accompany him.  I wore my ski pants so that I could be sure of keeping relatively warm and declared that I had no intention of getting my feet wet or of attempting to cross to the big rock; I would wait on what I deem to be my lookout rock, which is on the near side of the main channel between the two.  Unfortunately the look-out rock, so-called, doesn't allow a view of where he gathers the mussels but at least I can see that he gets across the channel safely, which is some comfort!

We went down to the beach about three quarters of an hour before what we know to be low tide.  This is a full quarter of an hour before the official low tide.  Given that we were nice and early we were not altogether surprised to see that the sea was still coming quite well in, although we hadn't anticipated quite how far!  Our destination was the rocks at the left and centre.


So we went off for a walk along the sunny end of beach to while away the time until the tide had receded further.  It was a glorious morning, crisp and cold and with a clarity of the air which comes after a dusting of cleansing snow:


The sea was producing large, vigorous and frothy waves but the major drama seemed reasonably far out from shore:


I took my time meandering along the beach pausing to take photos along the shoreline.  Heavy rain had filled the nearby stream and the unusual volume of water had forged a wide waterway to the sea.  Usually the outflow is slight and shallow.  On this day it was much more lively.  Here it is meeting the sea:


The swathe of water gushing forth was broad and sashayed out in front of a big rocky outcrop:


The low angle of the mid-winter sun picked out elaborate patterns in the near sandbank:




A variable oyster catcher rested on one leg, no doubt keen to soak up the sunshine after a very cold night:


The big skein of bull kelp showed that the tide had been moving with a vengeance, tearing it from its rocky home:


A close look at the surface of its dislodged 'holdfast' showed the contour of the rock to which it had been fastened, and revealed a colony of limpets which had made their home there:


The those great strands of kelp had grown from three stems which were close to being as thick as my wrist:


Having spent a while agreeably meandering along the far end of the beach we turned back.  Once back to our spot we stood watching the water.  The tide had gone out a bit.  The surges were still coming in rather a long way but then they drained out again.  Between surges I walked briskly to my usual lookout rock and Rewi did an experimental walk below the cliff face.  He was too slow and ended up climbing it - a little way. 


At that point we should have given up and gone home, but we didn't.  Rewi watched the water from closer nearby:


The water was retreating to what was close to the usual level of the low tide, and it looked as if getting across to the big rock should be straightforward, which is was.  I took this image from up on my rock, which was about four feet above the water level shown here, which was just as well:


To be honest even I didn't anticipate just how big some of the surges would turn out to be:


That's Rewi safely over there.  The water level in the channel in front of me filled up with a rush:


That water was really shifting:


Rewi was out of sight.  The channel behind me, which had been so devoid of water just minutes before, filled similarly:




I got very nervous.  I was high enough above water level but looking back to the beach I was uncomfortably aware that I was completely marooned. 


The big surges seemed to come in every couple of minutes.  Each time they came in the water took some time to ebb.  The time between them could be narrowing.  I waited anxiously for Rewi to complete his harvesting.  Usually it doesn't take him more than about a quarter of an hour, but even accounting for our earliness with the low tide it wasn't long before I started to panic.  From where I stood I couldn't see him.  This doesn't usually worry me too much, but given the force and height of the surges there was no way I was going to venture across that channel to check up on him.  He seemed to have been out there for longer than I expected and the time of low tide ticked nearer.  

With about five minutes in hand I waited for the water to ebb sufficiently, scrambled down from my rock and made a run for the high tide mark on the beach.  I still couldn't see him.  Again waiting for the water to recede I ran down closer - and there he was, quite safe and busily working away.  I called and called.  Over the noise of the sea he didn't hear me for a minute or two.  Finally he did.  "COME OUT", I called repeatedly, "COME OUT NOW!"  A big surge was coming in.  I was fairly high up the beach and the incoming water didn't look as if it would amount to much by the time it got there.  Some rocky humps nearby looked as if they would afford me enough height from the water.  Here they are photographed from further back:


I should have scrambled onto the one at the right:


But I didn't.  I had been on the lower one, which you can see below was inundated.  The water came in... and in... and by then it wasn't safe to hop down and run up the beach; I could only stand still.  I set my feet as steadily as I could while the wave came in over my feet, above my ankles, and then some.  I was wet to the knees.  After what seemed like an interminable length of time it slowly went out again.  I can tell you, with the certainty of that experience, that it's much harder to stand steadily against water which drags at your legs from behind than to withstand a wave from the front: the ebb-flow nearly had me off my feet and on my back - but not quite.  Here it is coming in over that same rock:


... And then further.  I took these photos about ten minutes later when I was at the point of making a run for it!


I was thankful that Rewi had finally heard me.  He stopped a few mussels short of the allowed quota and climbed back up his rock.  Heedless now of getting any wetter I ran to where I could see that he got safely back across the channel, and from there we both hustled back to high ground.  I had had a bad fright.  Although Rewi had got wet to the waist he wasn't admitting to anything of the kind.  However, it was far too close for comfort, and although it had been a calculated risk we learnt our lesson and won't take similar risks in future.  Neither of us had taken into account the height or the force of the surges.  I think we were both relieved to get back to the safety of high ground.  I know I certainly was - immensely so! 

The peacefulness of the sight of this small leaf on the sand signalled a return to more tranquil surroundings.  The pattern in the sand around it showed that the tide has washed over it before leaving it nestled where it was:


When we got home I checked the web for a reading of the swell height out in the open sea.  It had been 3.5 metres.  That is a big sea!  No wonder the sea had been pushed so far up the beach!  The combination of the level of the low tide and the surges from the big swells produced a low tide which would ordinarily equate to one in excess of a metre - quite unsuitable for musselling.  In addition, it was far more dangerous on account of its unpredictability!  In future I'll be checking the swell reading before we go out, as well as the level of the low tide!

Websites I use regularly:
  • Tidespy - adjust the map zoom to find markers showing swells and other data relating to your area
  • Met Service - click through on the Marine link part way down the page, and then click through to your location.
I have written three other articles about water safety.  The one linked to below is a companion article:
I have also written a number of others about exploring the beach and its rocky pools.  All my beach stories can be found by clicking on the link below:

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