Constant gales nothing new under the sun

 

Forecasting has changed, but severe Irish winter weather has not, writes Brendan McWilliams

This winter's storms have been remarkable more for their persistence than for their actual ferocity. Winter gales, after all, are a fact of life in Ireland and have always been. We lie close to the typical path along which active depressions make their way northeastwards at this time of year from the Atlantic over Scotland up towards Norway. Eight or nine days per month with gale force winds is more or less the norm along our western coasts.

But from time to time exceptional events occur. Noteworthy, for example, were the Christmas storms of 1997. There were two, you may recall, and they followed identical paths: one, the more severe, on Christmas Eve, and a second on Christmas Day itself, both bringing winds that gusted to more than 160km/hr, causing havoc with the electricity and personal tragedy in the form of injuries and several deaths.

Other very severe winter storms in the last century occurred in 1903, 1936, 1955, 1957 and, spectacularly, in 1974. It was during this last event, on the night of January 11th, that we experienced the highest wind ever recorded on this island: a gust of 198km/hr at Kilkeel in Co Down.

Looked at in this context, then, the recent gales have not been out of the ordinary. The highest gust recorded over the winter so far has been one of 146km/hr at Malin Head on December 31st. More typically this season's gales have brought gusts in the 100-120km/hr range - blustery enough but not exceptional.

But what has been strange has been the unusual persistence and duration of the gales. November began with a relatively calm week or two, but then we experienced what seemed like continuous rain and strong winds until the middle of December. The Christmas lull was short-lived, after which the gale force winds resumed to be with us almost continuously ever since.

Do we need a villain for all this atmospheric volatility? We could look, perhaps, to climate change and global warming, and indeed an increase in storminess in the middle latitudes is seen by some scientists - but by no means all - as being consistent with a greenhouse world. Or should we blame the currently incipient El Nino - that periodic anomalous warming of the tropical waters of the Pacific which has already contributed to a noticeable dearth of Atlantic hurricanes during the latter half of the 2006 season?

But no! The current El Nino, so far, shows every sign of being relatively weak, and even very strong El Nino episodes have only a marginal, barely detectable, effect on European weather. And we have no need to look to global warming either, since long spells of very windy weather have occurred before, and will occur again around our Irish coasts without any help from extra carbon dioxide in the atmosphere.

We cannot definitively say that the unprecedented warmth of our planet's atmosphere has had nothing whatever to do with all this windiness, but neither is it a necessary ingredient for explanations of this lengthy period of frequent gales. We live, after all, in a perennially windy country.

Much more remarkable, to this observer, as a sign that times have changed has been the faultless way in which all these gales have been predicted. Day after day, and often several days ahead, the severity of each storm and the extent of the short intervening lulls have been anticipated by forecasters with an accuracy which would have been unimaginable, say, 30 years ago. In some sense, at least, our weather is improving.