Good intentions 'aren't enough' when donating after a crisis such as Haiyan

Faced with heartbreaking images of the typhoon-ravaged Philippines - the sea of corpses, communities reduced to rubble, mothers clutching their hungry children - the world is watching an epic tragedy unfold and looking for ways to help. The big question is how.

In the aftermath of mega-disasters such as Typhoon Haiyan, experts say there are some basic rules for those eager to do good: Forget the rummage-sale clothes, the old toys and the kind of supplies that will only stack up undistributed or damage an already weakened economy. Do send a cash donation to a respected charity.

"It absolutely should be money," says Professor Kathleen Tierney, director of the Natural Hazards Centre at the University of Colorado-Boulder, a research group on the social aspects and impacts of disasters around the world.

"Whether it's the US or abroad, one thing that typically happens after a major disaster is people want to donate stuff. This creates enormous logistical problems, and people receiving donations they could never conceivably use, like winter coats sent to people in the Caribbean."

When disaster aid is not properly thought out "you can end up undermining the local economy", Tierney adds. "Once you ship building materials halfway around the world, it turns out you've ruined the market" for those in the area. "If you want to see economic recovery, you don't want to send so many supplies that you create a situation where people can't survive in a business sense," she said.

The Red Cross, for instance, buys goods locally or domestically after disasters to help revive the economy, curb transportation costs and help guarantee culturally appropriate items are being used, says Jana Sweeny, the organisation's director of international communications.

Sweeny says there is a natural tendency for people to want to help after headline-making catastrophes, but that altruism can sometimes be misguided.