Archive for August, 2011

Hurricane Irene: Economic Loss Estimates

Sunday, August 28th, 2011

On Saturday, August 27, 2011, Hurricane Irene struck the eastern seaboard of the United States, starting as a Category 3 hurricane (with winds up to 130 miles per hour), but remained a Category 1 hurricane (with winds up to 95 mph) for much of its northward path, and Sunday morning was downgraded to a tropical storm.

IEM estimates a total economic impact of between $2.2 billion and $2.6 billion, distributed according to table below. These estimates account for expected damage associated with storm winds, storm surge and flooding, and represent the expected replacement and repair costs of damaged property and normal business interruption losses (e.g., they do not include potential losses associated with closing stock markets). Though this storm will touch over 28 million people, we estimate a relatively small amount of sheltering requirements. The strength of the winds will not likely cause as much damage as the resulting flooding, and this will depend on many factors (e.g. coastal development, soil saturation, flood control capacity, length and depth of rivers and tributaries).

Economic Loss Estimates

Hurricane Irene Economic Loss Estimates

* Major cities are separate from counties, except New York City which has a number of counties.

Below are maps showing the top wind speeds in the counties affected by Irene. As we compile the data, we will show flooding in a similar manner. Stay tuned!

Hurricane-Irene_map-of-peak-gusts_MD-DEClick map to enlarge. Divisions in map represent designated census tract areas on August 26, 2011

Hurricane-Irene_map-of-peak-gusts_NJClick map to enlarge. Divisions in map represent designated census tract areas on August 26, 2011


Hurricane-Irene_map-of-peak-gusts_NY-CTClick map to enlarge. Divisions in map represent designated census tract areas on August 26, 2011

For additional information, please contact Dr. Lloyd Blanchard at 703-414-8141, or at

How can simulation help emergency managers solve resource allocation challenges?

Thursday, August 11th, 2011

Author: Ryan Langlois, Statistician, IEM

Disaster preparedness is complicated. In the face of limited budgets, it becomes even more complicated. With lives and critical infrastructure at risk, deciding how best to use limited resources to improve protection and response can be a daunting task for public officials. How can emergency managers determine where their funding and other resources are best spent? I’ve seen this question posed in a several places recently, given the string of major disasters we’ve seen in the last decade, especially this year’s earthquake and tsunami in Japan.

Technology is one solution. Through continuing advancements in the information technology sector combined with emergency management expertise and proven analytical practices, theoretical simulations can now be used by emergency managers to analyze all possible and credible strategies in preparing for all types of disasters. Simulations can model any particular hazard in millions of different situations, factoring in existing and proposed response strategies and human behavior to predict how existing response systems will perform and how effective proposed strategies will be. For example, Japan could have used a simulation to determine optimum evacuation routes and procedures based on local populations, road infrastructure, and community demographics. States and cities can use simulations to determine whether building new roads would help with evacuation. While these answers may seem obvious, the results can be counter-intuitive.

However, simulations are only as good as the supporting data and processes behind them. Effective decision making at any stage of an emergency – from prediction to response and recovery – relies on a considerable amount of data and information. Simulations today can account for all types of data related to an emergency, from hazard data to information on human behavior such as how people will behave in response to emergency warnings, evacuation orders, and more. Accounting for how humans will behave in an emergency is critical to understanding the real effectiveness of any proposed solution. The simulations must also be configured to include specific local information such as available warning systems, evacuation routes, and warning diffusion and population mobilization times, just to name a few of the required inputs.

By creating disaster and response simulations, officials can objectively weigh the values of different protective action strategies in response to a hazard. For instance, would it be better to shelter in place or evacuate in the face of a chemical or nuclear emergency?  What evacuation routes are most effective in specific situations? Would placing more sirens in communities speed response?  These questions can be answered by effective disaster simulations.

With a strong simulation tool, cost/benefit analyses for disaster preparedness can be conducted relatively quickly. The results can objectively identify which strategies have the greatest effect on improving protection, pointing officials to the areas where limited funding should be spent. Having an objective, scientific analysis to back the decision also helps in communicating the decisions to the public.

See how IEM is applying simulation to improve emergency management: