Huge Surf at Mullaghmore

Over the next few days the story of the winter for Irish big wave surfing (and given it’s stature in the scene now a major story for winter 2011/12 globally) will start to hit the web. We’re already seeing photos of what looks like some of the largest surf ever ridden at Mullaghmore with waves that’d rank against any around the world for size and power.

The back story to this swell is almost as interesting. Early in March the US experienced severe weather conditions as warm air from the Gulf of Mexico hit a cold front over the mainland. The storm system created wreaked havoc across the tornado belt. Forecasters are already talking about this storm as one of the worst in history for this time of year, with 45 comfirmed tornadoes and a further 77 reported. This same system continued to roll north bringing a late season spell of winter weather to the northern US.  Moving over Eastern Canada the storm system split briefly before gathering strength over the ocean and heading north towards Greenland. At the same time a second, weaker, storm developed over Florida and moved up the coast and into the Atlantic.

What happened next was a combination of (for Irish surfers) extremely favourable conditions. The jetstream, the path of strong upper atmosphere wind responsible for the strength and development of sea level storm systems, itself decided to cooperate and a powerful, sustained SW flow deepened the second system and sling shot it at such an angle to join forces with the first storm extending it’s power and, most importantly, size.

At this stage on wednesday 7th March the storm created had westerly gale force winds extending for over a 1000 miles of ocean pointing at Ireland and Scotland. Crucially a phenomena known as the Greenland Jet Tip exaggerated the inital storms power. The topography at the tip of Southern Greenland creating a funnel of extremely strong westerly winds. This effect has created this stretch of oceans deserved reputation as the windiest on the planet. No bad thing for Northern European surfers.

This next image shows the development of the swell. You can clearly see the influence of the Greenland Jet Tip in creating the largest waves. The other interesting facet of this chart is the location of the swell. The circle lines define the typical window for big waves swells hitting Mullaghmore. You can see from the charts that this swell came in right in the northern edge of this window. Mully is a typical point break in many ways, as swell wraps around the headland it loses size and power and the further south a swell originates the more this is an issue. However there’s a cut off for the benefits of north in the swell with too much of a Northerly direction causing waves to section and closeout. At 297 degrees at it’s peak on arrival this swell flirted with the northerly edge of the optimum window and in doing so allowed the maximum possible ridable wave size to be realised from this huge swell.

We’ve been working hard to improve our swell charts recently. One of the major developments we’ll put live shortly is a new colour scheme to give greater clarity to exceptional swells. This extends the range from dark red, through on into purple and ultimately grey to black for the very most exceptional swells. This swell is one of the occasions where this change came into it’s own:

The same Jetstream track that worked so well for that second system encouraged this storm to continue to the North of Ireland. The result might have been slightly smaller waves (the coast of Scotland scored the full brunt) but did mean the local winds were nothing like as strong as have been seen on previous storms and from a favourable SW direction. The results? Waves like this:

So just how exceptional was this swell? Combine the size of the swell, with those contestable local winds and a swell direction giving maximum impact on the reef and there’s nothing quite like it in our archive. Checking the records we’re looking at storms in the size range about 5 times in a decade (most recently the tow comp near miss of the 13th December 2011). Ignoring the ones that arrive with storm force winds (the issue with Decembers swell) and you’re talking about 3 times a decade historically.

The other exciting aspect of this swell, from our perspective, is that it actually cropped up in the MSW forecast models over a fortnight ago. As we headed towards the end of the Billabong Tow Comp window we had a catch up with contest organiser Paul O’Kane, we discussed the poor outlook towards the end of the window but did mention a hint (and it was just a hint at this stage with a large swell showing as a modest probability on our 16 day forecasts) of this storm in the outlook*. Quite sensibly Paul had to take a view to the logistical and safety aspects of extending the window for such a possibility which made it impossible in this case.

* Operational 16 day forecasts will be available publicly on MSW shortly.