Why La Niña Matters for Surfing

Tony Butt

by on

Updated 154d ago

It’s the beginning of the season and everyone in the northern hemisphere is anticipating the swell deluge.

In the North Atlantic, will there be a continuous stream of moderate to strong low pressures tracking across the north, generating clean, long-period swells, like 1992-1993? Or will there be huge high pressure stuck in the middle of the Atlantic for weeks and weeks, with virtually no swells and cold east or northeast winds, like 1986-1987?

Or perhaps all the storms will track too far south, producing huge, onshore surf and torrential rain in Portugal and swells that fail to reach areas further north, like the Weird Winter of 2009-2010? Or maybe it will be so big and stormy that only the most sheltered, east-facing spots will be surfable, like the extreme winter of 2013-2014.

Remember the extreme winter of 2013 and into 2014? It was January 2 of '14 when this incredible swell started as a disturbance in North America. It eventually formed into Hercules, one of the biggest swell events in modern history. Also, it came off the back of 2013 being the second hottest year ever without an El Niño event (the year 1850 was the first) Why's that important? Read on...

Remember the extreme winter of 2013 and into 2014? It was January 2 of '14 when this incredible swell started as a disturbance in North America. It eventually formed into Hercules, one of the biggest swell events in modern history. Also, it came off the back of 2013 being the second hottest year ever without an El Niño event (the year 1850 was the first) Why's that important? Read on...

Predicting the kind of surf we are going to get this winter, to any degree of exactitude, this early in the season, is not straightforward. Let me explain why.

For predictions to have a reasonable probability of coming true, they have to have the right amount of precision according to the amount of time in the future you are predicting. It’s a juggle between three factors: certainty, precision and lead-time.

For example, if we are predicting the surf for tomorrow, we can be quite precise with the wave height and wind conditions, because it is only a short-term forecast. But if we are trying to predict the surf six months into the future, and we still want a reasonable chance of it coming true, we have to be much, much more vague about it. The atmosphere and ocean are so complex, and contain so many intertwined processes, with feedback loops and tipping points, that things quickly get very confusing when we try to predict even more than a week ahead.


Ok, but what the heck is El Niño and La Niña?

This La Niña year has been crazy for Australia.

This La Niña year has been crazy for Australia.

© 2023 - Aaron Pierce.

There are a couple of large-scale atmospheric patterns that can give us a general idea of what’s in store for the next couple of months. The one that has been studied the most is the El Niño Southern Oscillation (ENSO). The ENSO is a cyclic ocean-atmosphere pattern that flips from one state to the other – from El Niño to La Niña – every two to seven years or so. It originates in the South Pacific, but affects many other parts of the world, including the storms that produce surf in the North Pacific. It might also affect the storms in the North Atlantic, although scientists are still not sure about that.

How the jet streams take a different path during La Niña and El Niño.

How the jet streams take a different path during La Niña and El Niño.

The reason ENSO affects the storms in the North Pacific is because it affects the trajectory of the upper airstream. The upper airstream is the major driving factor behind the storms on the surface. During El Niño years, the mid-latitude or polar jet stream (the upper airstream that flows at latitudes around 40-60 degrees north) is pushed further south and made stronger. As a result, the surface storms also track further south, creating bigger and often more ragged surf in California, and bigger swells at northwest exposures in Mexico (think Todos Santos).


Does it impact surf in the North Atlantic?

If only everyone could say, 'hey, La Niña means days like this forever and ever...' Isaac Marshall under cover in the UK.

If only everyone could say, 'hey, La Niña means days like this forever and ever...' Isaac Marshall under cover in the UK.

© 2023 - RT Shots

In the North Atlantic, it might have a similar effect, although the jury is still out. During the Weird Winter of 2009-2010, for example, which was an El Niño year, California had constant big swells. In the North Atlantic, the polar jet, and hence the storm-track, was pushed way to the south, which resulted in good surfing conditions in unusual places like Cabo Verde or southwest-facing spots in Ireland, but poor surf in France, Spain and Portugal.

At the moment the ENSO is in the La Niña part of the cycle. In the North Pacific, La Niña winters are known for bringing smaller-than-usual surf to California. The polar jet tracks too far to the north, making a lot of storms deepen off the coast of Canada and Alaska, generating shorter-period NNW swells instead of those long-period west swells that are so good for spots like Maverick's. Maybe the fact that we have a La Niña situation at the moment means that there will be epic surf in these areas this winter? Or maybe not

In contrast, in the North Atlantic, a more northerly storm-track is good news for spots in France, Spain and Portugal, spots that thrive on big, long-period swells from the northwest. Maybe the fact that we have a La Niña situation at the moment means that there will be epic surf in these areas this winter? Or maybe not.

One thing that scientists do agree on, is the influence of ENSO on Atlantic hurricanes. During El Niño years, the subtropical jet stream (not the polar jet stream, the other one that flows at latitudes of around 30 degrees north) is pushed south and is stronger than normal.

The subtropical jet crosses over Central America and into the Caribbean, right where the hurricanes are. The strong air flow at high altitudes causes what is known as vertical shear. Vertical shear is when the wind below and the wind above blow from different directions or are different strengths, literally producing a shearing action, like scissors. This interferes with the physics of the hurricanes, so they are less likely to form and less likely to grow.

Therefore, we can say that when there is El Niño, there are less hurricanes, and the ones that do form are weaker than normal. This basic idea is a relatively simple and direct cause-and-effect relationship, backed up by many years of scientific studies.


But it's not as simple as El Niño bad for Atlantic surf, La Niña good, right?

December 1997 showing the strongest El Niño on record. This chart simply graphs the average surface wave height (of all swells combined) and shows a temperature difference of +3.57°C

December 1997 showing the strongest El Niño on record. This chart simply graphs the average surface wave height (of all swells combined) and shows a temperature difference of +3.57°C

Sort of, and sort of not really, it is much more nuanced than that. It ought to follow that during La Niña years, the hurricanes are stronger and more numerous. Like this year. And that is what the experts at the National Hurricane Centre have been saying – that we are in for a more active than usual Atlantic hurricane season. Even though, up to the end of August there had only been three named tropical storms and not one hurricane. Only now, at the beginning of September, are things starting to get moving.

The slow start wasn’t expected by the experts at NOAA and the National Hurricane Center. Which makes you think; If something as heavily studied as the Atlantic hurricane season, with the most sophisticated mathematical models running on the most powerful computers in the world, can’t be predicted really accurately, where does that leave us trying to predict the surf?

We can be philosophical about it. We know for certain – almost 100% in fact – that there is going to be bigger surf in the winter than in the summer. The inclination of the Earth relative to the Sun means that, in each respective hemisphere, there is a greater temperature differential between the equator and the pole in the winter than in the summer. And that temperature differential is what drives the storms. As far as I know, that’s not going to change anytime soon. Unless of course we get hit by a meteor or something that throws the planet off its orbit.

Perhaps the best thing is not to worry about what sort of season we are going to get. Best thing is to be always ready for that big swell that might be just around the corner.

Cover shot by Henrique Casinhas