Factors that provided protection at Sissano
a). We can observe that, for no obvious reason, the wave had more energy in some sectors than in others. Perhaps this is something to do with the shape of the sea floor immediately offshore. This is hard to prove and difficult to use as a guide.
b). Of more practical use is the observation that at different locations thickets of trees provided some protection. The minor scale of damage at the Sissano clinic probably was due to both a less energetic attack by the wave and protection by trees.
c). The wave normally will lose energy as it progresses inland and will cause less damage after it has travelled 400 m or more. However, there are exceptions as will be discussed next week.
We can see reduced damage beyond 400 m at Sissano mission, where buildings south of the road were undamaged, and at Nimas where, despite the massive and widespread destruction of the entire village, three or four houses that were 400 m from the coast were spared. These house were partly protected by trees.
We continue next week with some new ideas on the importance of the shape of the land surface and the value of drainage channels.