A hurricane is an organized weather condition that produces winds at high speed. The winds need to be above force 12 on the Beauford Scale which will consequently bring torrential rain and can destroy flimsy structures.
Hurricanes are known by various different names, depending on where they occur in the world:
- Hurricane: Caribbean and North Atlantic, eastern Northern Pacific, western Southern Pacific
- Cyclone: Arabian Sea, Bay of Bengal, southern Indian Ocean
- Typhoon: China Sea, western Northern Pacific
- Willy-willy: north-west Australia
Hurricanes develop over the ocean when the water is at its hottest – usually during the late summer. The warm air creates a low pressure core around which winds begin to rotate. If this continues, these winds can reach speeds up to 186 mph (300 kph) or even higher (shudder). In the northern hemisphere, the winds rotate counter-clockwise, but in the southern hemisphere, they rotate clockwise.
The strongest winds are usually 10 – 12 miles (16 – 19 km) from the center of the hurricane, typically called the “eye”. Strangely enough, the eye is the calmest part of the storm, but is only temporary as the storm is constantly moving. The “eye” itself may be from 4 to 30 miles (6 to 50 km) wide, and up to 300 miles (500 km) in diameter for the largest and more intense hurricanes.
Hurricanes can form at any time during the year, but in the Northern Hemisphere, the main season is June to November and in the Southern Hemisphere the main season is November to April (especially January to February). Hurricanes are not a feature of the South Atlantic.
Hurricane Patterns
Hurricanes will build up force when out at sea and gradually begin to veer towards the poles. Hurricanes are prevented from developing in the upper levels of the air by the prevailing westerly winds. In any case the wind speed will usually be the greatest on the pole ward side of the eye. They can travel as fast as 30 mph (50 kph) wrecking havoc and devastation on island and along shorelines in their path. However, they will usually start to slow down when they reach the mainland – usually to about 10 mph (16 kph).
Hurricane Warnings
Meteorologists use satellite surveillance to monitor hurricane development far out in the ocean, to track their progress and to give warning of their approach. Some hurricanes move very erratically, so (sailors in particular) forecasts should be monitored very closely in hurricane areas.
If you don’t have a radio to alert you and you happen to be near the shore, the growth of a swell can be an indication of an approaching hurricane. When taken in combination with other conditions, such as highly colored sunsets or sunrises; dense banners of cirrus cloud (see pic#1 below) convergence towards the center of the approaching storm; abnormal rises in barometric pressure followed by an equally rapid drop (assuming you have a barometer).
Pic #1: Cirrus Clouds
If you are in a solid building and on high ground STAY WHERE YOU ARE – travel in a hurricane is extremely dangerous. The safest place is usually in a cellar or under the stars. Store drinking water as both water and power supplies may be cut off during the storm. Also, have a battery-powered radio to keep in touch with any instructions issued. If you are not in a sturdy structure, evacuate to a hurricane shelter. Shut off power supplies before you leave.
Seeking Shelter
If you are outdoors, a cave will provide the best protection. The next best option is a ditch. If you are unable to escape or find adequate protection, lie flat on the ground so you will be less of a target for flying debris. Crawl to the lee side (side sheltered from the wind) of any really solid shelter such as a rocky outcrop or even a wide belt of large trees. Beware of smaller trees or fences that could be easily uprooted.
Safety Precautions
Get out of the hurricane’s path if you can.
- Hurricane warnings are generally issued when a hurricane is expected within the next 24 hours. This should give you plenty of time to evacuate the area, if you are prepared.
- Keep away from the coast, if possible, where the destruction will be the worst due to flooding and tidal waves. Also, stay away from river banks that will likely overflow very rapidly, usually before you have time to react.
- Board up windows and secure any outdoor objects that could be blown away.
- If out at sea, take down all canvas, batten down the hatches and stow all gear.
Survival Advice
Stay where you are when the hurricane appears to have passed. There will usually be less than an hour of calm as the eye passes overhead and the winds begin blowing again – this time from the opposite direction. If sheltering outdoors, move to the opposite side of your windbreak in preparation for the change in wind direction, or, move to better shelter if it is close by.