SAS Urban Survival Handbook (114 page)

VIOLENT STORM

Wind speed:
103-114 kph (64-71 mph)

Beaufort scale:
11

Likely effects:
Large branches snapped off trees. Shallow-rooted trees may fall. Roof and other structural damage. Fences blown down. Lorries blown over. People blown over.

HURRICANE

Wind speed:
117 kph plus (73 mph plus)

Beaufort scale:
12 and over

Likely effects:
Widespread damage. Weak structures flattened, roofs blown away. Trees blown down. A large amount of airborne debris. Windows blown in. Shelter for people essential.

No one can explain exactly why a hurricane develops. It starts at sea as a centre of low pressure. Given the right combination of atmospheric conditions, it can gather energy from evaporated water in the ocean, whipping into a whirling windforce. The result is a spiralling catherine-wheel effect, with a calm ‘eye’ in the centre, which may exceed 40 km (25 miles) in diameter.

A hurricane could cover 1.3 million square kilometres (500,000 sq miles) and last up to three weeks before blowing itself out, usually over land. Small wonder that anything caught in the eye is virtually helpless. The eye of Hurricane Carla in 1961 was packed so tightly with trapped birds that observatory weather planes were unable to fly through it!

Enormous destructive power aside, the hurricane has another deadly secret weapon—unpredictability. Despite world observatories’ facility to spot and monitor hurricane activity, thanks to satellites and radar, there is still no way to predict when and where a hurricane may strike.

Hurricanes are able to ‘loop the loop’ without warning—Typhoon Wayne doubled back on itself three times before hitting China in 1986. International collaborations such as Spectrum (formed in 1991) have been set up to conduct research into hurricane behaviour, but it will be years before reliable warnings are possible.

These days, the catastrophic effect of hurricanes is being reduced as a result of better designed housing in affected areas. On the Florida coast, for example, the hurricane death toll has fallen over the last 20 years, even though the area is more densely populated.

When Cyclone Tracy hit Darwin, Australia, in 1974, only 400 of the city’s 11,200 houses survived relatively intact. Darwin has been almost totally rebuilt with hurricane-proof structures but (fortunately) they have yet to be tested.

Naming hurricanes

Since 1953 hurricanes in the Atlantic, Caribbean and Gulf of Mexico have been given personal names devised by the World Meteorological Organization as a means of identification. Originally they were named only after women, supposedly because of their unpredictable and capricious behaviour! These days they are named alternatively with male or female names. Revised every six years, the names run alphabetically. 1991 hurricane names, for example, are Bob, Claudette through to Victor and Wanda. In the event of an extremely damaging hurricane a name is retired permanently.

Early warnings

Tracking stations around the world constantly monitor hurricane activity and provide up-to-date information to weather services. There are two types of hurricane alert:

Hurricane watch
This means that a hurricane MAY threaten coastal and inland areas, but it does NOT mean that a hurricane is imminent.
Action:
Listen for further information on your local radio and television stations and be prepared to act promptly.

Hurricane warning
This means that a hurricane is expected to strike WITHIN 24 HOURS.
Action:
Keep listening for advice from local authorities and act according to recommended emergency procedures.

Getting prepared

Before hurricane season:

• ◑ If you do not have a storm cellar, know where your nearest evacuation shelter is—it could save your life.
  
• ◑ Check your house is sound, particularly the roof. The strongest winds in a hurricane occur immediately after the transit of the eye and blow in the OPPOSITE direction. It is then your house will be most vulnerable.
  
• ◑ Keep your property clear of junk—a hurricane can turn it into missiles.
  
• ◑ Check emergency supplies.
  

After a hurricane warning

• ◑ Keep the radio/TV on for more information and instructions. Watch out for warnings of tornadoes—often spawned by hurricanes.
  
• ◑ Fill car with petrol and be prepared to evacuate if told by the emergency services to do so.
  
• ◑ Leave low-lying/coastal areas that might be swept by high tides or floods.
  
• ◑ Leave mobile homes for substantial shelter. Caravans are prone to overturning in strong winds.
  
• ◑ Secure outside objects. Even fridges have been known to take flight in hurricanes.
  
• ◑ Board up windows to prevent breakage through debris or wind pressure.
  
• ◑ Store drinking water in clean bathtubs, sinks and containers. Water systems may be damaged or contaminated in the storm.
  
• ◑ Lock up pets.
  

During a hurricane

• ◑ If you are unable to evacuate and you do not have a cellar, shelter in the strongest part of the house—under the stairs, perhaps. Take emergency supplies with you.
  
• ◑ Do not shelter near an internal chimney breast. Even in Britain’s gale of October 1987 people were killed when chimneys collapsed through ceilings.
  
• ◑ If the house starts to break up, protect yourself with mattresses and blankets or get under a strong bed.
  
• ◑ Stay inside—high winds and flying debris can be lethal.
  
• ◑ Do NOT drive—cars are no protection in a hurricane.
  
• ◑ Do NOT be fooled by the calm eye! If the storm centre passes directly overhead there may be a lull lasting anything from a few minutes to an hour, before the wind picks up to hurricane speed again in the OPPOSITE direction.
  

After the storm

• ◑ Apply first aid to any casualties.
  
• ◑ Stay where you are until given the all-clear.
  
• ◑ Listen for information on radio/TV stations.
  
• ◑ Do NOT go sightseeing—you may interfere with rescue work and put yourself in danger.
  
• ◑ Drive ONLY when necessary—roads may be littered with debris and should be kept open for emergency services.
  
• ◑ Do not use telephone unless an emergency. You could tie up lines needed for rescue services.
  
• ◑ Report broken power cables, water, gas and sewage mains.
  
• ◑ Prevent fires—fire-fighting could be impaired because of low water pressure.
  
• ◑ Eat perishable foods first if electricity is cut off—you don’t know how long you may have to rely on your existing food supplies.
  

TORNADO

The low, train-like rumbling of a tornado approaching is indeed an awesome sound, for it brings with it one of nature’s most violent storms. With whirling winds of up to 300 kph (about 200 mph), a tornado has a funnel-type effect causing everything in its path, apart from the most solid structures, to be sucked up as if into a giant vacuum cleaner. The pressure is sufficient to lift light buildings—at the very least, doors and windows can be sucked out.

Fortunately, the base of a tornado is usually only 25-50 m (82-164 ft) across, which reduces the level of destruction to a smaller area. Also, unlike hurricanes, tornadoes normally only travel up to 16 kilometres (ten miles) before petering out. That is not to say that their power should be underestimated! Tornadoes can strike at any time of the year and often occur on the fringe of hurricanes.

Even Britain has had its share of tornadoes, albeit on a small scale. The Newmarket tornado of 1978 caused £1 million of property damage. In 1981, 58 tornadoes were reported in one day in an area from Anglesey to the eastern coast.

Tornado precautions

Emergency procedures before, during and after a tornado warning are much the same as for hurricanes, though there are a few extra precautions which should be taken:

• ◑ The best protection is an underground shelter or basement of a steel-framed or reinforced-concrete building. If none of these is available, take cover on the lowest floor in the centre of the house, under a strong table, making sure there are no heavy appliances above. This should reduce the risk of injury if walls collapse. Stay away from windows!
  
• ◑ As the tornado approaches, CLOSE all doors and windows facing the storm and OPEN all those on the opposite side. The aim is to equalize pressure inside and outside to prevent the roof being sucked away or the building collapsing.
  
• ◑ If outside, do not attempt to escape—not even in a car.
  
• ◑ If there is no shelter nearby, lie flat in a ditch or ground depression and cover your head. You will stand less chance of being sucked up by the tornado or hit by flying debris.
  

FLOOD

Flooding may not have the same dramatic impact as an erupting volcano, say, or the effects of a monumental earthquake, but it is probably one of the most common and widespread natural disasters worldwide. The statistics are horrendous.

Flooding can occur for many reasons—heavy rainfall (particularly in valleys after prolonged spells of hot dry weather), snow melting on mountains, rivers changing course, dams collapsing and high tides in coastal areas. The Thames Barrier in London was constructed to prevent flooding during a North Sea surge. This is where high tides combine with low pressure and north or north westerly winds, as far away as Scotland, to push waves down the eastern coast of England, gathering force and raising sea levels.

Living close to the sea is immensely popular, despite vulnerability from eroding sea walls, but the squeeze for land has meant housing estates may be built in (frankly) unsuitable areas, such as the flood plains of rivers. If ‘global warming’ has the effects predicted, it is estimated that by the year 2050 sea levels could rise by as much as 50cm (20in). It may not sound much, but it could mean that many areas of the world could be drastically affected by the constant threat of floods.

Getting prepared

Fortunately, weather centres can usually predict flooding and so give early warning to local authorities and the media. Advance warning can be anything from a few hours to a few days, so there’s normally time to organize yourself before water starts heading your way.

Before the flood

• ◑ If you live in a known risk area, find out the official flood height which will affect your house (from your local council) to help you act accordingly.
  
• ◑ Listen constantly for radio and TV reports.
  
• ◑ Turn off electricity as threat becomes more immediate. Do NOT wait until water has entered the house and risk electrocution.
  
• ◑ Turn off gas in case of potential damage and leaks.
  
• ◑ Block gaps outside doors with sandbags, usually provided by the emergency services. If not available, improvise with plastic bags or pillowcases filled with earth or gravel, or stuff cracks with old blankets and carpets.
  
• ◑ NEVER stack sandbags round the outside walls to keep water out of a basement. Water seepage could cause pressure that could damage the walls or even raise the basement out of the ground. Better to fill the basement yourself with clean water if you think flooding will occur. It will equalize pressure to prevent structural damage and will make cleaning up afterwards easier.
  
• ◑ Sandbag exterior windowsills if it looks like water will rise that far.
  
• ◑ Move to the upper floors, taking emergency supplies, pets and any valuables/papers you simply cannot live without. REMEMBER: Lives are more important than possessions.
  
• ◑ Take spare clothes and shoes with you—the flood may be around for days.
  

  FLASH FLOODS
  

  Flash floods can be deadly and highly unexpected, unless you know the danger signs. They are common when torrential rain follows a long dry spell. The ground cannot absorb the rainfall quickly enough and the flood begins.
  

  Alice Springs in Australia’s ‘red centre’ suffers from an incredibly arid and desert climate with summer temperatures around the 45°C (113°F) mark. So permanently dry is the town’s Todd River that they hold an annual Henleyon-Todd Regatta. Competitors run up and down the river bed in bottomless boats with their legs sticking out (like ‘Flintstones’ cars)! Yet every couple of years surprise storms transform the river bed from a barren desert to a raging torrent. Many people have drowned under the force and speed of the first onslaught of water.
  

  Flash floods occur all over the world. If a flash flood is imminent or leaves you stranded outdoors:
  

  • ■
    Seek shelter on higher ground immediately. REMEMBER: You don’t have to be at the bottom of a hill to be on low ground!
    
  • ■
    If your car stalls, abandon it. You and your vehicle could be swept away
    
  • ■
    Do not try to swim—the currents are deadly
    
  • ■
    Do not try to cross a fast-moving stream unless you are POSITIVE it is no more than knee height. It may look safe, but the current could still be strong enough to sweep you off your feet
    
• ◑ Fill baths and containers with water—supplies may become contaminated.
  
• ◑ Brightly coloured cloth is useful for signalling for help.