By Professor Hannah Cloke, hydrologist, Water@Reading
If you knew there was a strong chance that your local river was about to burst its banks and sweep away your house, you’d get yourself, and your family, out of harm’s way.
Yet tragically, despite major advances in flood forecasting, hundreds of people every year still die in floods. Either warnings are not getting through, or people and authorities are failing to take appropriate action.
Severe flooding brought on by a strong coastal El Nino has left more than 90 dead and hundreds of thousands homeless in Northern Peru [photo: Maria-Helena Ramos]
This month has again seen severe flooding in many parts of the world, including Peru and Australia, leading to loss of life and destruction of homes and livelihoods.
We will never be able to stop such awful floods. But there are some vital steps that we can take to reduce the risk from these events and to save lives.
In recent years we have been taking great strides in our capability to provide early flood warnings, so that people can prepare for upcoming floods – often before it even starts to rain.
The Water@Reading research group at the University of Reading works alongside flood forecasters to develop better forecasts and warnings, such as those of the European Flood Awareness System (EFAS) and the Global Flood Awareness System (GloFAS), part of the EU’s Copernicus Emergency Management Service.
But how do we know if we’re doing a good job? How can we convince people that the warnings are accurate, and worth acting on?
When an El Niño is declared, or even forecast, we think back to memorable past El Niños (such as 1997/98), and begin to ask whether we will see the same impacts. Will California receive a lot of rainfall? Will we see droughts in tropical Asia and Australia? Will Peru experience the same devastating floods as in 1997/98, and 1982/83?
El Niño and La Niña, which see changes in the ocean temperatures in the tropical Pacific, are well known to affect weather, and indeed river flow and flooding, around the globe. But how well can we estimate the potential impacts of El Niño and La Niña, and how likely flooding is to occur?
By Dr Andrew Charlton-Perez, Department of Meteorology, University of Reading
Former BBC weather forecaster Bill Giles’ criticism of weather forecasts raises questions about how weather is communicated generally.
Mr Giles has hit out at forecasters for regularly warning the public about the potential consequences of imminent severe weather, arguing they are ‘behaving like nannies’ and could cause the public to become ‘immune’ to the advice.
Rain in Reading – watch out for that puddle!
He added the practice of naming storms had become too frequent, and that forecasters should only advise people about potential dangers for ‘exceptionally severe weather’, which occurs once every few years.
But how much weather information is the right amount for the public? How much do they understand? Could an appreciation of the uncertainty of forecasts actually improve our faith in them?
Research at the University of Reading has shown that not only is the average person able to process more complex weather forecast information, they are likely to make better decisions as a result of the additional information.
Scientists at Reading have therefore begun looking at whether the way weather predictions are presented to the general public can be improved.