Never any Hurricanes - yet very tropical

[Al in Kona]

When we visited Malaysia some years back I remember visiting the state of Saba and they called thmselves "The land below the wind", meaning they were basically free from Typhoons or Cyclones (hurricanes). Seems most tropical areas that are within about 10 degrees of the equator do not experience these violent storms. For example, in Central America, Nicaragua has suffered from hurricanes on rare occasions but apparently Costa Rica and Panama have not. Can someone explain the reason for this?

[amazondk]

Al,

I am believe it has to do with the rotation of the Earth and it's impact on the formation of weather. The doldrums are in this latitude range. I am too far away from the ocean to have a hurricane anyway. But, over on the coast it is still impossible at my latitude. What does happen in Brazil, but not at my latitude, are what the call extra tropical cyclones. There is a cold current running up Brazil from Antartica. But, there is a circulation that does create near hurricane force winds that sometimes hit southern Brazil. But still without the true impact of a hurricane.

dk

[elHoagie]

Al,

As Don mentioned, it's mostly due to the rotation of the Earth. The rotation of the hurricane is caused by the coriolis force, which makes it rotate counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. At the equator there is no coriolis force, which is why tropical cyclones tend to weaken if they get close to the equator. I've always heard latitudes less than 5 degrees are pretty safe.

Costa Rica is at a fairly high latitude (8-9 degrees), but that lack of hurricanes there is caused by something different. Most hurricanes in the northern hemisphere tend to move west, north, or some direction in between. Since the huge land mass of South America is south and east of Costa Rica, there is no path across an ocean for a hurricane to take before making landfall in Costa Rica. But, Nicaragua is just north of South America, so a hurricane can move due west across the Caribbean and make landfall there.

[Jeff in Costa Rica]

Thanks Jack, great explantion! Most people don't realize that Costa Rica is further south than the northern tip of South America. The northern parts of Columbia and Venezuela protect us (and Panama) from hurricanes.

They are building a large marina in Quepos and that is one of the selling points....no hurricanes here.

[ed110220]

Here's a map from Wikipedia showing the tracks of all tropical cyclones from 1985-2005. As you can see tropical cyclones are rarely if ever encountered in a band about 5-10 degrees from the equator. They are also absent from the South East Pacific and South Atlantic, with the exception of Cyclone Catarina that struck the coast of Brazil in 2004. This was reportedly the first recorded South Atlantic tropical cyclone.

[TikiRick]

What I never quite understood is all the theories behind the warmer the water, the more intense the storm. Why then does a storm intensify as it travels further north over cooler waters. The coastal waters off the California and Mexican coasts are relatively cool water, yet strong storms still develop.

[amazondk]

Ed,

That is a great map.

dk