Maxima of absolute anisotropies observed during the early phases of the events. The observations have been ordered into three different classes (see text) that appear in the left, middle, and right panels. Red symbol fillings denote that the anisotropy may be underestimated because of poor pitch-angle coverage, black fillings mean that the pitch-angle coverage was sufficient. The dashed lines mark the borders that define the different anisotropy classes (see text).