We're in the Bahama now and we seem to get suck in a blow at least once a week, for a day or two, or so seems, while we're in George Town, Exumas. That's not so bad. Last year while we were at Great Harbour Cay, in The Berry Islands, the blows would last for an entire week. But what is a blow?
A blow is when strong air comes into the area and we, as sailors on a boat, have to find protection. What I mean by protection is that we have to be tucked close to land so that the land mass protects us from the waves. Large waves are not fun at all on a boat at anchor, I don't even like them when we're sailing.
What causes a blow?
Gases move from high-pressure areas to low-pressure areas. And the bigger the difference between the pressures, the faster the air will move from the high to the low pressure. That rush of air is the wind or blow. The air can be still one day, and the next, powerful gusts of wind can knock down trees. The main cause of wind is the differences in temperature between different areas.
When gases in our atmosphere warm up, the atoms and molecules move faster, spread out, and rise. That’s why steam coming off a pot roses upward. When air is colder, the gases get slower and closer together and the air sinks. The sun hits different parts of the Earth at different angles, and because Earth has oceans, mountains, and other features, some places are warmer than others. Because of this, we get pockets of warm air and cold air that lead to different temperatures and different pressures. Since gases behave differently at different temperatures, we get pockets with high pressure and pockets with low pressure. When warm air rises, it leaves behind an area of low pressure behind it then here comes the wind! Gases move from high-pressure areas to low-pressure areas and the bigger the difference between the pressures, the faster the wind or blow.
Here's a blow that we were in while we were anchored in Key Biscayne, Florida with no protection. Key Biscayne is a large, mostly protected bay, but the wind came towards us in a direction that we were not protected from.
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