Alone Like a Rolling Stone

The kitchen of origin of hurricanes

It's hard to believe, but hurricanes often take a long run-up to wreak havoc in the Caribbean or on the U.S. East Coast. Off the west coast of Africa, they find ideal conditions to form. Here, water temperatures are 27°C and higher, there is a moisture-labile stratified atmosphere, the wind field near the ground is convergent, that at altitude divergent, and there is only a slight vertical wind shear. For the whole structure to start rotating, the Coriolis force must still be sufficiently large. This is given from 5° northern or southern latitude.

Calhau, Cape Verde Eastside

Except for the Cape Verde Islands, there is then nothing in between as far as America. The energy, namely the warm water, is available in vast quantities, and so the tropical disturbance becomes a tropical depression, a tropical storm, and finally a hurricane. Wind speeds of up to 120 knots are then possible, in gusts even above that. With a speed of 10 - 15 knots, these formations usually move west to northwest, exactly in our planned route. That's why we haven't set off yet. Since we sail on average about 5 knots, these things catch up with us relatively quickly. Statistically, the most storms occur in September, in October they become much less and in November the probability of encountering such a storm is low. Since tropical storms don't have a frontal system, the only thing left to do is to watch the barometric pressure and have a good weather app. As described in, a previous post, we want to download data via the Iridium satellite system. After I published the post, I got a hint from a reader that there are SIM cards that allow unlimited data transfer. We have now obtained this SIM card. For $135 we now have 150 voice minutes and unlimited data transfer. However, dealing with the software and establishing contact with the satellite are still, more than uncomfortable. Everything that exceeds a data size of 100kbyte is almost impossible to transfer. By the way, the small "k" stands for kilo and not for M like Mega or G for Giga, which are the usual download sizes today, for example when downloading movies or software from the Internet. Yes such a small file needs, with disconnecting again and again, up to one hour. At least we have a weather forecast as a Grib file. Now it is only necessary to apply the right strategy. First we wait for September. Since as said, the occurrence of the hurricanes in October, are already times clearly smaller. Next, we stay at the southernmost edge of the northeast trade wind to avoid the dangerous quarter of the hurricane.

In the Aluguer Taxi

Until the time comes, we look at the weather on the island of Santo Vicente. We take the Aluguer to the east of the island. Calhau is the name of the inconspicuous place in the middle of nowhere. No, in the middle is not true, it is rather at the end of the world. People on the street, inhabited houses, a small store, all missing. Restaurants, the few, closed. Yes, even the road stops here. We discover a sandy beach and walk the two kilometers or so. The water is crystal clear, the wave breaks on a sandbank about 300m from the beach, you stand waist deep in the water and can have a lot of fun. Here we meet three people who share the beach with us. The wind carries the clouds from the east. Only because of the too flat mountains on Santo Vicente, they don't get stuck and don't rain down. Thus, the land is quite dry and there are only a few areas that are irrigated by wells. On the way back to the main road, we then still find a restaurant where we get something to drink. 

The first choice transport

We are waiting for an Aluguer to take us back to Mindelo. If there's one thing you can count on, it's the Aluguers on Cape Verde. The cars drive always and everywhere. You just have to have a little patience. Ours arrives after half an hour and with another passenger we start the return journey to Mindelo. The tropical lows usually pass south of Cape Verde, so that it rains, especially in September, but the amount of rainfall is still within limits. We are here now for five weeks and it has rained only in a single night, once something. We will see how it develops and slowly start to prepare for our Atlantic crossing. When it is so far, you will find out here on our channel Until then, as always, fair winds and keep a stiff upper lip.