*4.4. Wave Storm Seasonality*

The polar plot shown in Figure 7 presents the date of occurrence for each storm at locations south of Tenerife, with the bubble size indicating storm energy, *E*. It is easy to observe the existence of two distinct climatic seasons, one remarkably mild, from April to October, and other relatively stormy, which extends from November to April, although the period of occurrence for more energetic storms is restricted to a shorter time span, from December to March, approximately. This is the period when severe storms are detected in the southernmost places, while extreme storms reach the southwestern locations from November to April, and the southeastern coastal strip is influenced by less severe wave storms from mid-November to mid-April. An interesting, but rare, feature is the detection of two relatively moderate energy storms at location IP5 during summer. These storms are associated with intense trade wind events, generating moderately severe wave conditions and arriving at this location traveling from the NNE-NE, through the GC-T channel.

**Figure 7.** Polar plot of (*Hm*0)*max* and the timing of its occurrence throughout the year at all inner points in the southern flank of Tenerife, for the period 1958–2020. Bubble size indicates storm energy.

Generally speaking, extreme storms occur mainly during winter, between December and March, with a substantially lower probability of presentation during spring and autumn, becoming practically null in summer. Accordingly, Rayleigh and Kuiper tests clearly reject the hypothesis of uniformity at any level of significance. In other words, extreme storms are not randomly distributed around the circle (i.e., along the year) but concentrate during late autumn, winter, and early spring, with the more intense conditions observed during winter. Henceforth, the used tests allow us to accept the existence of a seasonal pattern in the timing of extreme wave storms on a statistical basis. It is interesting to note that the tests indicated above have been applied to be rigorous in the analysis, although, in this particular case, the simple observation of Figure 7 provides qualitative confirmation of this fact.
