*4.3. Wave Storm Severity*

The severity of wave storms has been evaluated by estimating the total wave power, *TWP*, as in Equation (1), and storm energy, *E*, as in Equation (2). Results obtained at the outer flanks of the Canary Islands for the period covered by the datasets are shown in Figure 6a. Numbers next to each point indicate the number of identified storms, while values in brackets stand for the threshold used to select the events, corresponding in each case to the associated *Q*99.9. It can be observed that the highest values of *E* and *TWP* are located on the western (EP6, EP7, EP8) and northern (EP8, EP1, EP2) flanks of the archipelago, since these are the sides most exposed to harsh wave fields reaching the islands from directional sectors with north and/or west components. On the contrary, the average energy and total wave power of wave storms detected south or east of the archipelago are substantially lower due to sheltering effects against the direct action of storms approaching from any directional sector, except for those travelling from the SW and S sectors. Points EP4 and EP3 are special cases. The first is located at the south but in the middle of the channel formed by Gran Canaria and Fuerteventura, through which waves coming from the NNW-NNE can propagate. Point EP3 is placed at the eastern side of the archipelago, so that wave directions at this point are restricted to NE-SW. It should be noted that proximity to Africa imposes significant fetch restrictions for wave propagation from the east.

**Figure 6.** (**a**) Average wave storm energy, *E* and *TWP*, at the outer flanks of Canary Islands (1958–2020). Numbers next to each point indicate the number of identified storms and, in brackets, the threshold used to define such storms. (**b**) Average values of *E* and *TWP* at inner points south of Tenerife for the same period. Numbers next to each point indicate the threshold used to define wave storms.

It is worth mentioning that the thresholds established at each point to select the storms follow the same pattern as the average value of the storm energy. However, this is not the case for the number of wave storms, which is very similar for all the outer locations around the archipelago. Nevertheless, this result is totally consistent since wave storms are defined as a function of the threshold that changes from point to point.

Storminess conditions for inner points located at the southern coasts of Tenerife are shown in Figure 6b, which indicates both the storm energy and total wave power, as well as the selected storm threshold at each point. Results reveal that the average storm energy and total wave power are larger in the southwestern and southern strips, exposed to relatively severe wave storms approaching from the southwest sector, as well as to storms travelling through the G-TF channel from the northwest. It must be stressed that, on this edge of the island, in the vicinity of points IP1 and IP2, are located the most famous beaches of the island. Wave conditions change substantially in the southeastern strips because these areas are protected against wave storms approaching the islands with northern, western, and even southern components. Energy reaching these points comes almost exclusively from the NNE-NE direction, coinciding with the predominant direction of the relatively weak trade winds.
