One of the most powerful hurricanes on record slams into the southeastern United States, packing ferocious winds and killing 25 people. A few days later, a far weaker tropical storm hits Haiti. Some 2,500 are killed and thousands more displaced.

When natural disasters strike, some people are more vulnerable than others.

What determines different communities’ susceptibility to the impact of hazards? Why did Americans get off relatively lightly when Hurricane Ivan hit in September 2004, while Tropical Storm Jeanne proved catastrophic for people in Haiti?

A cocktail of factors made Haitians more vulnerable, including a lack of early warning systems and extensive deforestation that causes floods and landslides.

At the root of it all is poverty. People in rich countries like the United States – including poor Americans -- have better access to the kinds of resources that help to prevent disasters becoming crises in the first place, and to cope with them when they do.

Hazards happen. But it’s mainly in poor countries that they turn into humanitarian disasters by claiming lives and robbing survivors of their livelihoods. It’s no coincidence that 98 percent of people killed or affected by natural disasters live in developing countries.

But it isn’t just about economics. Your age and gender may make you more at risk in a disaster than your neighbours, as may the environment in which you live.

Below we explore the link between poverty and vulnerability, and explain which groups are at special risk in natural disasters.

Why does being poor make you vulnerable?

Women

Children

The elderly

The disabled

People in conflict zones and other emergencies

WHY DOES BEING POOR MAKE YOU VULNERABLE?

If you know a place is prone to natural hazards such as floods and earthquakes, there are various things you can do to prepare for the worst. You can set up early warning systems and organise evacuation procedures. You can build houses strong enough to withstand tremors and put up barriers to keep out the sea.

Such projects require adequate resources, effective governance and strong community links.

But now imagine you’re a street vendor in the slums of India’s Gujarat state after the devastating 2001 earthquake.

Your fragile shanty home didn’t stand a chance, and you were seriously injured when it collapsed around you. You’re already on the margins of society and have little hope of getting health care. You’ve lost your only means of eking out a living.

It’s not hard to see why poverty and vulnerability are intertwined.

And things are getting worse. The International Federation of Red Cross and Red Crescent Societies (IFRC) projects that by 2025, more than 50 percent of people in developing countries will be vulnerable to extreme-weather hazards like floods and storms.

Disaster experts explain vulnerability in terms of physical, social, economic and environmental factors. In developing countries, poverty tends to bring out the worst in all four areas.

A recent report entitled Before Disaster Strikes by non-governmental relief agency Tearfund highlights some of the ways this happens.

According to Tearfund, up to half the people living in the largest cities of the developing world - or about a billion people - now live in unplanned squatter settlements.

“Many squatter settlements lack even the most basic infrastructure - health and fire services, dykes and drains, telecommunications, piped water and sanitation - and are therefore ill equipped to cope when disaster strikes,” the report says.

The problems outlined go beyond rapid urbanisation.

The effects of climate change such as rising sea levels and greater numbers of storms are likely to hit the poor hardest because they tend to live in the worst-affected areas and can least afford to adapt.

Poor people are often forced to build in risky places – the sides of ravines, near volcanoes, on flood plains -- because they are marginalised from safe and legal areas.

Poor people are more likely to resort to harmful environmental practices such as deforestation and slash-and-burn agriculture, which increases the risk of flooding and landslides.

Poor people, often marginalised politically, socially and geographically, may not receive early warning of disasters and lack the voice to protect their interests. People are often very reluctant to evacuate and leave their homes unprotected, for fear of losing their few possessions.

The correlation between underdevelopment and disasters is made clear in the IFRC’s latest World Disasters Report. While natural disasters claim on average 51 lives per disaster in highly developed countries, the figure is a staggering 589 deaths per disaster in countries of low human development.

HIGH-RISK GROUPS

Women

After the December 2004 tsunami crisis in Asia, the International Labour Organisation (ILO) argued that more attention should be given to gender issues in tackling the crisis.

“Women are more vulnerable during disasters because they have less access to resources, are victims of the gendered division of labour, and they are primary caregivers to children, the elderly and the disabled,” writes the ILO’s Rochelle Jones.

“This means that they are less able to mobilise resources for rehabilitation, more likely to be over-represented in the unemployed following a disaster, and overburdened with domestic responsibilities leaving them with less freedom to pursue sources of income to alleviate their economic burdens.”

Women are also vulnerable to sexual violence and exploitation - including trafficking - in the aftermath of disasters.

Rights groups have expressed concern over unconfirmed reports of Sri Lankan women being raped in shelters for people displaced by the Asian tsunami. Similar reports surfaced in Guatemala after Hurricane Mitch in 1998.

Children

Experts say children orphaned by disasters such as the Bam earthquake in southern Iran 2003 and Asia’s tsunami in 2004 bear psychological scars that may never fully heal, including feelings of deep guilt.

“It’s not a matter of psychological care -- it’s a question of survival,” Noriko Tarukawa, a Tsukuba university professor who has studied orphans of the 1995 Kobe earthquake, told Reuters.

Children are also at risk of abuse following disasters.

The United Nations says some children orphaned or separated from their parents by Asia’s tsunami have fallen prey to criminal gangs bent on selling them into slavery.

Children account for at least a third of the 150,000 killed by the tsunami, and the United Nations says up to 1.5 million may have been affected.

“Their vulnerability means they are among the most at risk of the diseases that now threaten to kill thousands more,” Heather MacLeod, international child protection director for relief charity World Vision, said in a statement.

“And history has shown us that the humanitarian response to a disaster can often increase the vulnerability of children.”

The elderly

As a group, the elderly are often among the most neglected in disaster relief programmes -- yet they are among the most vulnerable.

Up to half of those killed in the 1995 earthquake in the Japanese city of Kobe were elderly -- a disproportionately high number given that they only made up around 14 percent of the population.

Relief charity HelpAge International says the vulnerability of the elderly is on the increase, with the number of older people in developing countries projected to double to 850 million by 2025. Those 850 million would account for 70 percent of older people worldwide.

“For older people in emergencies, isolation from family and community support sharply increases levels of risk,” the agency says in a briefing paper.

“Abandonment, discrimination and self-exclusion are not uncommon. Older people may need special protection in refugee camps and support to cope emotionally -- especially when they have suffered repeated loss and displacement throughout their lives.”

The disabled

Relief charities such as Handicap International make it their business to help people whose permanent or temporary disabilities have left them marginalised and less able to restore their livelihoods after a disaster.

For example, many Afghan women who suffered crushing injuries in a 2002 earthquake were unable to marry or earn a living.

Other disabilities can make people vulnerable. People with limited mobility were at high risk during the Asian tsunami, simply because it was harder to flee the killer waves.

The challenge after disasters is often to get walking aids such as crutches and prosthetics to disabled survivors, yet these items are usually difficult to find in poor countries and are a low priority for most aid agencies.

Such problems may be especially prevalent in conflict zones such as Sri Lanka and Indonesia’s Aceh province, where landmines and unexploded ordnance are rife.

People in conflict zones and other emergencies

According to the United Nation’s disaster reduction body, the International Strategy for Disaster Reduction, 140 natural disasters coincided with complex political emergencies in Africa, Asia, Latin America and Europe in the past five years.

Decades of conflict in Afghanistan meant that when a drought came along in 1999, people’s ability to cope was severely limited due to a lack of resources. The coincidence of drought and conflict-related displacement in southern Sudan in early 1998 triggered a famine notable for horrendous malnutrition and mortality rates.

Conflicts and political emergencies also can make it hard for aid to get to the people who need it most after a natural disaster.

After the Indian Ocean tsunami devastated Indonesia’s troubled Aceh province, fears that foreign aid workers could be shot or kidnapped threatened to hinder relief efforts outside Aceh’s two biggest cities.