Number 30, October 2001

Editorial

Vulnerability and Risk Assessment: A Contribution of the Weather Research Community in Developing an Effective Response to Terrorism

The death toll from the September 11 terrorist attacks on the World Trade Center and Pentagon is approaching 5,000. It has been years since so many fatalities resulted from a single event in this country. Until now, the greatest conflict-related loss on American soil occurred in 1862 during the Civil War battle along Antietam Creek, when over 3,600 lost their lives in a single day. Approximately 2,390 perished in the Pearl Harbor attack.

In the 19th and early 20th centuries, severe weather events in the U.S. caused enormous human losses. As many as 12,000 people were killed by the Galveston hurricane of 1900, and 2,200 perished in the 1889 Johnstown flood. Our hemispheric neighbors still experience natural disaster-related losses of this magnitude. Hurricane Mitch killed upwards of 11,000 Central Americans in 1998, and the 1999 Venezuelan landslides and flooding resulted in 30,000 deaths.

The U.S. avoided these kinds of losses in the late 20th and early 21st centuries. Tornado deaths declined from around 1.8 per million people in 1925 to approximately .12 per million today. The last hurricane with a death toll in the thousands struck in 1928. The potential for sizeable hurricane-related fatalities remains significant, however. Improved forecasting, advanced warnings, better communications, public awareness, spotter networks, evacuation, construction techniques, building codes, and infrastructure-as well as climate fluctuations, demographic changes, and luck-- have all played a role, although the contribution of each of these factors is not well understood.

With such a large amount of experience dealing with disasters, what contributions can the weather research community make in developing an effective response to terrorism? The weather research community's expertise in both risk assessment-characterizing the threat of harm -and vulnerability assessment-characterizing the susceptibility to be harmed--can help form the intellectual backbone of the nation's response to terrorist attacks.

Risk refers to the potential for loss of life, property, business capacity, societal and political stability, and environmental quality. A risk assessment determines the likelihood of adverse impacts from a specific hazard to the built, natural, business, and social environments by estimating the chance that an event will occur and the consequences if it does occur.

Vulnerability refers to the level of exposure of human life, property, and resources to damage from a hazard. A vulnerability assessment of the built environment in the context of severe weather would examine factors such as the concentration of populations and development relative to a severe weather risk; the value of exposed property and the proportion that is insured; how well existing buildings have been constructed to withstand hazard forces; the resiliency of transportation, utility, and communication links and facilities; and what mitigation measures are in place. A societal vulnerability assessment would look at the vulnerability of people of different income levels, ages, genders, skills, and experiences to a hazard. A business vulnerability assessment explores issues such as whether a business has an up-to-date disaster plan, proper disaster supplies, and business interruption insurance. Risk and vulnerability assessment helps decision makers develop and prioritize appropriate responses to disasters such as investments in research, mitigation, disaster planning, and recovery efforts.

The dramatic reduction in loss of life from hurricane-related storm surge in the U.S. over the last 30 years is an excellent example of the weather community's successful use of risk and vulnerability assessment. Until 1970, storm surge was responsible for 90% of hurricane-related deaths near the U.S. coast. Yet from 1970 to 1999, only six deaths out of 600-a total of 1%--have been linked to storm surge. While climate and good luck may account for some of this change, much of the success can be attributed to changes in hurricane policies and operations such as the development of risk assessment technologies based on modeling of potential storm surge inundations. These projections are used to develop emergency preparedness plans and actions - a form of vulnerability assessment -- for coastal areas.

The U.S. General Accounting Office (GAO), an arm of the Congress, recommends that threat and risk assessment play a key role in the development of a national strategy for responding to terrorism. The first step of such an assessment would be for a multidisciplinary team of experts to identify and evaluate threats in terms of a terrorist's capability and intent to attack, the likelihood of a successful attack, and its consequences. While natural hazard risk is often estimated quantitatively through a combination of scientific analysis and historical data, terrorism risks would have to be estimated qualitatively from the best available intelligence information. The next step would be to create a list of potential terrorist attack scenarios. The final step is a prioritized list of risks based on threat-asset-vulnerability combinations that are used to select countermeasures. As of August 2001, four states had completed such assessments, and the FBI is coordinating two national-level threat (but not risk) assessments.

It is likely that over $1.8 billion will be budgeted to fight bioterrorism in the next fiscal year. Congress has already enacted a $40 billion emergency spending package in reaction to the September 11 attacks. Allocations likely will increase as the "war on terrorism" expands. The information obtained from risk and vulnerability assessment can assist decision makers in determining how to allocate resources to reduce society's vulnerability. Without such assessments, countermeasures may be based on worst-case scenarios, resulting in the overfunding of some programs and the underfunding of programs addressing more likely threats. For example, the Department of Health and Human Services has in the past stockpiled certain drugs and vaccines that were not responsive to the intelligence community's assessment of the most likely chemical and biological threats. The weather research community's expertise in risk and vulnerability assessment is a resource of knowledge and experience that should be tapped in developing effective responses to the threat of terrorism.

Bobbie Klein
Center for Science and
Technology Policy Research
bklein@colorado.edu

References:

Arguez, A. and J. Elsner, 2001: Trends in U.S. tropical cyclone mortality during the past century.

Brooks, H. and C. Doswell, 2001: A brief history of deaths from tornadoes in the United States.

Doswell, C., A. Moller, and H. Brooks, 1999: Storm spotting and public awareness since the first tornado forecasts of 1948.

GAO, 2000: Combating terrorism: Issues in managing counterterrorist programs (GAO/T-NSIAD-00-145).

GAO, 2000: Combating terrorisms: Linking threats to strategies and resources (GAO/T-NSIAD-00-218).

Rappaport, E., 2000: Loss of life in the United States associated with recent Atlantic tropical cyclones. Bull. Amer. Met. Soc. 81(9), 2065-2073.