Disaster risk management

It seems there will be rain. A storm is coming, and there is an unusual amount of rain - over this town, inland, and in the mountains nearby. It rains for weeks, and the flow of the water in the river increases. There is a flood, at first on the fields, and then in the town. The harvest is swept away.

Houses and cars are destroyed. A bridge collapses. And … eight people are pulled away by the water masses and drown. The town and the inhabitants have been struck by a natural disaster. When all is over, the people start to rebuild what’s been damaged.

They wonder: Can this happen again? Can we protect ourselves from it? And if so, how? Yes, it can happen again. Floods are rare, but at some point it will likely rain as much again.

This cannot be prevented by humans. That is why people need to find new ways to protect themselves. They must identify the risks they live with. They assess how probable it is for something to occur, and how serious the consequences will be. They make a risk analysis.

From the risk analysis they create a plan for how to protect themselves. Some decide to move. They build houses higher up on the hills where the water cannot reach. They avoid the danger. But not everyone is able to build a new home.

You can’t move a whole town just like that, and the fields where they grow food are placed near the river because the crops grow the best exactly there. The population instead builds walls around the fields and in the town. The walls are high to keep the water away. Also, they dig a canal around the town. If there is an unusual amount of water in the river, some of it can be led away by the canal.

It is a diversion channel. They prepare in other ways too. They monitor the weather, and the amount of water running in the river inland. When there are unusual amounts of rain coming in and you can see a risk for floods, a warning is issued on the radio and TV, and to mobile phones. When this alarm is sent out, people are urged to leave the areas that might flood.

People are told to evacuate. For everyone to know what to do and where to go, they practice. Once each year they pretend there is a catastrophe, to practice on what to do. This way they are better prepared when the real catastrophe happens. But if they still can’t manage to protect themselves, if the water destroys houses and bridges and railways again, then everything needs to be repaired.

And this costs money. Because of this, the inhabitants in the town start to save up together in a special account, a fund. The money is for people who lose homes and possessions, and to rebuild devastated parts of the town. They also keep food and medicine in supplies far from the river. All of these measures and preparations are results of the risk analysis.

In other places people live with other risks. Here, in California, both large earthquakes and major wildfires are common. They take human lives and destroy homes. Here too, people try to protect themselves in different ways. Many buildings are made to sway during an earthquake not to collapse.

They try to thin out forests by chopping trees. Thanks to this, fires cannot spread as easily. In Japan, they are used to both earthquakes and enormous flood waves from the oceans, tsunamis. There, they protect themselves with both walls, and systems to warn people if a flood wave approaches. But earthquake-proof houses, protective walls and warning systems cost a lot of money.

It is expensive to protect from the forces of nature. This is why you always have to look for the measures that provide the best protection for the money. This is one part of making a thorough risk analysis. In the little town by the river, people have come far with the rebuilding. The destroyed bridge is repaired and - Look! - out on the field new crops are already growing.

And hopefully, the inhabitants' risk analysis and their measures protect them when the next flood approaches.