How does Timothy know about the approaching storm and how does he prepare in The Cay? Why is he afraid?
One "very hot morning in July", when the trade winds are uncharacteristically not blowing, Timothy and Phillip hear a "crack like d'rifle". Timothy knows that it is the waves that make the noise, "somewhar far off, out beyond d'Grenadines, or in dat pesky bight off Honduras", and that is means that a hurricane is brewing. There is "a breathless silence" around the cay, and although the sea is as "smooth as green jhelly", the water is already getting cloudy and the sky has "a yellowish cast to it". Timothy knows how to read the signs of the sea and the sky, having lived on the islands and the water all his life. He says that most storms do not come until September or October, and that the few that come in July are very dangerous, "wid all d'death upon it".
To prepare for the storm, Timother lashes their water keg high on a palm trunk at the highest point of land on the cay, then ties the remaining rope "securely around the same sturdy tree". If the waters reach that point, Timothy and Phillip will have to stand at the tree, locking their arms into the rope so as not to be swept away. The two then have a huge meal, because they do not know when they will be able to eat next, and then Timothy puts his knife into the tin box containing the valuables they will need for survival, and lashes that high up in the tree with the water keg.
In his long life, Timothy has been in many storms, and he recognizes this will be one of the fiercest he has ever seen. He is afraid because he knows the damage a hurricane can do, and realistically, he realizes that despite their preparations, he and Phillip may not survive. Also, he has the added worry that, should he alone perish, Phillip will have to survive on the island, alone and blind, clinging to the hope that one day he may be rescued (Chapters 13-14).