Living With Hurricanes

Hurricane Floyd

As a sailboat vagabond, life is inextricably linked to the elements; when your home is pinned in place by a pick on the end of a rope, you can’t help but develop a sensitivity to anything that has the potential to rock your equilibrium. Tidal flows & currents can create a resonance in the ocean surface that set the boat rolling from side to side for hours, heavy rain showers can fill the dinghy, and an impending hurricane means running for your life.

From www.wunderground.com

I Have to Confess, I was bit of a Hurricane Ignoramous!

I’ve lived in the tropics often over the years, and always loved the rainy season’s “big warm rain”, I even had a fairly close encounter with a waterspout once, but this is my first experience of living in the hurricane belt.  Like most cruisers, I traveled south at the beginning of June (start of the Hurricane Season in the Caribbean) to Grenada which lies at 12°North of the equator.  The probability of hurricanes here is low enough for most insurance companies to consider it an acceptable risk, although there have been a couple of hurricanes passing over Grenada in the last few years; notably Hurricane Ivan which caused severe damage and killed 39 people on 7th September 2004, and Hurricane Janet, which passed over the sister island of Carriacou a bit further North less than a year later.

The following diagram shows the frequency of hurricane activity in the Caribbean by month....in September watching the storm predictions was literally like a game of bagatelle, with a new system being launched from the coast of Africa every few hours!

Hurricane Season: From www.wunderground.com

Hurricane Predictions & Forecasts

The University of the State of Colorado issue annual probability predictions for the North & South Atlantic based on weather trends and historic data going back 58 years (as at 2010).  The first prediction comes out in April each year and is updated from time to time during the season based on current year behaviour.  For the past few years the predictions have been extrapolated into a country by country landfall probability table for the US and Caribbean by Bridgewater State College.

From then on, it comes down to individual weather forecasts, of which there are many, to provide up to date predictions based on meteorological behaviour as it happens.  Websites such as Storm Pulse and Wunderground give great pictorial models of every weather system that has the potential for hurricane formation and these are updated twice daily.

Each “Invest [no.]”, as designated by the by the National Hurricane Centre, sparks the collection of extra data and initiation of prediction models from, amongst others, the Naval Research Laboratory and the University of Wisconsin Cooperative Institute for Meteorological Satellite Studies.

Formation of a North Atlantic Hurricane

Monitoring of a potential system (Invest) begins as an area of low pressure moves away from the East Coast of Africa and begins to travel westward across the Atlantic.  Where an area of convection develops, with warm moist air rising from the sea, facilitated by the low atmospheric pressure, the system is named a Tropical Disturbance and generally becomes of interest to weather watchers when it’s 100 nautical miles or more in diameter and it’s been in existence for 24 hours.

If conditions are right, this disturbance has the potential to develop further into a Tropical Depression (winds <38mph), A Tropical Storm winds 39 to 74mph), and finally a Tropical Cyclone or Hurricane (winds  >74mph) by the time it reaches the Caribbean.

The process of hurricane formation is explained very clearly in the following presentations from Florida Today& BBC News:

Click here to go to Florida News presentation

Click here to go to BBC News presentation

Hurricane Tracking & Dying

Hurricane rotation is caused by the earth turning – the Coriolis Effect – which deflects the air being drawn into the weather system.  Hurricanes spin anti-clockwise in the Northern hemisphere, and clockwise in the South, but they tend not to form within 300 miles either side of the equator where the Coriolis Effect is negligible.

The path of a hurricane is determined by a number of factors:
•    The storm follows high sea temperatures which will continue to feed it, e.g. in the Gulf of Mexico,
•    Existing wind conditions & pressure systems cause deflection, and
•    The Coriolis Effect bends the path to the right in the Northern hemisphere

Click here to watch the Movie

Eventually the hurricane reaches a place where it’s denied its feed of warm moist air; this may be because it’s veered out into the Northern Atlantic where sea temperatures are lower, or because it’s made landfall.  It’s dissipation over land is further helped by the uneven land mass which breaks up the wind streams.

What Price Paradise...

As with all good things, life in paradise comes at a price and in this case it’s the threat of hurricanes that tempers the sweetness.  At least living on a boat, I can take my floating home to a safer place if danger approaches….those on land aren’t quite so fortunate.

Yacht Ibis  offers adventure sailing holidays with relaxed tuition for singles, couples or groups & families of up to 5 people.  We operate from Grenada during hurricane season and sail throughout the Windward & Leeward Islands between November & May.