1. A method of controlling a wind turbine, comprising: acquiring and storing training data relating to one or more sensed variable, the training data comprising a feature vector obtained from at least one statistical measure indicative of risk; assigning each of the training data to a risk category based on a measured parameter and defining feature zones for each category from at least a measure of distance of feature vectors in that category, the feature zones including a high risk zone indicative of a high risk of a gust; and during operation of the wind turbine, determining an estimate of gust risk by calculating a feature vector periodically from data obtained from at least one sensor and determining to which of the feature zones to assign the feature vector, thereby determining an estimate of the risk of an extreme gust represented by the measured feature vector.