What just happened is not completely exceptional on a statistic level. The general situation was a disturbed north-westerly blow, one of the typical patterns of this area in winter. We have a low pressure zone centred on the British Isles, and a high pressure system over the Azores : the air flow is canalised in this corridor, and the winds are rather strong.
What the navigators encountered on Tuesday and caused so much damage is in fact the consequence of a smaller low that built up within the disturbed general flow, and which came to its maturity in the Cape Finisterre area (western most tip of Spain). This phase of development is called "cyclogenesis", and that's where very strong wind variations are observed (as Philippe Monnet, skipper of Sopra Group explained, "I never saw the wind become so strong so quickly", editor's note).
If you add to that the fact that the system is moving very fast, you get Force 8 to 10 winds (exceeding 45 knots/87 km/h), with very strong gusts. We had planned a southern route for Lionel at the exit of the Channel, then he was to tack to west in order to avoid the biggest part of the disturbance : he had just done so when Gitana's X mast broke', says Sylvain.