Where do waves come from?

Before we go into forecasting whether there will be surf on any given day, first we must understand where waves come from and how they are generated.

So how come some days we have waves that seem bigger than the Jolly Green Giant and other days a ripple only Stuart Little (the mouse) could surf? Well first we need to understand the formation of waves, this is not for the faint hearted….so please bear with us.

STEP ONE

It all begins…..with little bumps that are called capillary waves (often referred to as ripples). These are caused by wind blowing over the surface of the water, some of the winds can push down on the sea making up and down motions on its surface.

STEP TWO

Wind pulsing around the same area can then add to the motion and make it grow bigger…up and down, up and down. Once these dips are more pronounced more wind will be able to effect the dips surface area and in turn allow them to grow bigger and bigger.

UNSCIENTIFC EXAMPLE

PLEASE DO NOT TRY THIS AT HOME (UNLESS YOU WANT A VERY WET BATHROOM FLOOR)

If you imagine sitting in the bath full of water and you move backwards and forward. The water in the bath will start to move in the same way as you.  If you then continue to move backwards and forwards in time with the water, you will create a bigger wave….until the water is spilling over the side of the bath…not quite a scientific accurate comparison, but you get the drift.  (You are the wind)

STEP THREE

Waves begin to travel. Waves do not carry water from A to B, they carry energy.  If you picture a stadium full of people and imagine them all to be a particle in the sea. The Mexican wave begins at one end of the stadium, the same people that start that wave do not move, but pass on the wave to the next person and so on….so it is the motion/energy that is passed on.  The waves travel from the ocean or the sea towards the coast.

What causes the winds that we need to generate surf?

So where do these winds initially come from?  What is the starting point??? This is where it gets even more complicated and to be honest unless you have a degree in physics it can be confusing.  To put it simply, we need Low pressures.  Low pressures in our atmosphere, suck in the surrounding air which creates movement (wind).  This wind then moves across the surface of water out at sea and starts the process detailed above.

People used to forecast waves using Surface Pressure Charts…

So do we just need a low pressure????

I am afraid it’s not quite that simple.  The low pressure needs to be in the right location for us at Saltburn to get surf.  If it is over the land….no wave, if it is hovering over west coast of Scotland….no wave. The low pressure needs to track across the North Sea or to the east, south east of us. If you look at the Isobar chart below you can see the Low Pressure which will affect us….(big swirl above UK). The further the Low pressure is away from us the more lined up it will become when it reaches us.

Think of our Coastline