Dogwash

From the Daily Mail:

A scientific model based on ‘probability’ rather than fact was used by the government agency to forecast the spread of the volcanic ash cloud, according to critics.

Erm, the scientific method involves creating a 'model' and then testing to see how well the 'observed reality' corresponds to what the model predicts, as far as this can indeed be measured, and then either revising the model or making more predictions. In some cases the test may be satisfactorily binary: true or false, the model is either conclusively disproven or, for the time being at least, we may accept the result as tentatively valid. In others, especially when dealing with horrendously complex and only partially understood systems like fluid dynamics, the model will (a) involve drastic simplifications (like the 'billiard ball particles' of Newtonian mechanics) and (b) involve a statistical rather than an absolute result. If the prediction seems to match reality 95% of the time, say, we might be onto something.

An aeroplane falling out of the sky with its engines trashed would be a fact, or possibly even a Fact. Predicting the distribution of suspended volcanic ash is a touch more on the probabilistic side, as is predicting the deleterious effect of this ash on turbine engines.