Engineers working at Colorado State University have created a multi-hazard hurricane impact level model, which estimates economic damages caused by storms before they happen.
Forecasters typically describe approaching storms by categorizing sustained wind speeds on the Saffir-Simpson scale. Wind speed, however, is not usually the main cause of death and destruction from hurricanes, the researchers say.
Instead, the greatest impacts are usually caused by flooding, precipitation, and storm surge, combined with geography of landfall, population density, and quality of infrastructure.
The researchers wanted to come up with a more accurate way to talk about impacts, so they focused on a storm's expected economic damage.
The impact model is detailed in a recent paper in Palgrave Communications, authored by Hussam Mahmoud, associate professor of civil and environmental engineering, and Stephanie Pilkington, a graduate student in civil engineering, who designed and validated the model.
Mahmoud and Pilkington's impact model uses artificial neural networks and machine learning to "teach" a computer program how to predict a pending storm's damage, by dollar figure. The neural network, which is like an artificial human brain that gets smarter as it receives more data, is powered by historical data from several storms. These include Hurricane Katrina in 2005 and Hurricane Arthur in 2014.
The researchers used this data to train neural networks to connect storm characteristics to known outcomes from those storms. To feed their model, they used publicly available data from federal agencies. Their model uses inputs including estimated landfall, population affected, maximum wind speed, maximum storm surge and total precipitation.
They then tested the model in real time during actual storms, including most recently Hurricane Harvey, which hit the Gulf Coast around Houston, Texas, in August.
The researchers also used their model to analyze whether physical and policy improvements such as seawalls, the National Flood Insurance Program and updated building codes have mitigated the impacts of powerful storms. In short, they haven't, the researchers say.
According to their data, coastal communities in Florida or Texas are about as economically vulnerable, or even worse off, to hurricane devastation as they were 100 years ago.
The number of people living in coastal communities has increased in 100 years, and with it, infrastructure and highways. "Improved building codes and other changes have not been enough to keep up with the sheer volume of wealth, infrastructure and people in those areas," Pilkington says.