Improving Situational Awareness During a Nuclear/Chemical Attack

The threat of a chemical or nuclear attack is a clear and present danger that emergency planners, managers, and responders must prepare for each and every day. In particular, the threat of a chemical or nuclear weapon detonation in a major city within the borders of the United States is a very real one, particularly in light of the 11 September 2001 terrorist attacks. In the event of such an attack, maintaining a continuing communications capability would be of critical importance both in establishing situational awareness and in preparing neighboring cities and towns for mass evacuations or influxes.

When an attack is chemical or nuclear in nature, chemicals and/or radiation are released into the air in the form of a plume. This plume poses the most dangerous threat, to both life and property, because it travels with the current weather pattern and can spread over a very large area. By mapping the dispersion, emergency managers can in most cases immediately determine the direction of its movement and provide the guidance needed by residents either to shelter in place or to evacuate to a safer location well away from the CBRN’s projected path.

Ventura County, California, has developed plans to prepare for such an event and to be able to quickly provide the best – i.e., safest – evacuation routes. Given the fact that nearby Los Angeles is one of the nation’s largest cities, and therefore a particularly inviting target for would-be terrorists, Ventura County must be prepared to facilitate either a mass evacuation or a sudden influx of similar magnitude. To be able to do so, the planners of the Ventura County Department of Public Health, working in close cooperation with other county agencies, established the Ventura County Plume-Mapping Working Group.

Life-or-Death Decisions – With Little or No Information Available! All of the Working Group members fully understand the need to maintain immediate and continuous situational awareness for the county – and that the county itself must be fully prepared to provide the public at large with accurate evacuation information in the immediate aftermath of a nuclear/chemical event. The Working Group members also understand that, in many similar situations – not involving nuclear or chemical weapons, though – local response agencies and county officials do not always have immediate or full access to the critical information they need from the epicenter, and also receive very limited if any support from federal, state, and/or regional mapping agencies in the initial hours following an attack such as that postulated.

In preparation for such difficult circumstances, members of the Working Groupentified and developed redundant local plume-mapping capabilities of their own that will help them obtain the information they would need about a radiological release immediately after an incident occurs. It is vitally important – not only for emergency managers at the scene of the attack but also for others in the surrounding areas – to have such information available in the immediate aftermath of the attack, or as soon thereafter as possible. Possession of such important data provides emergency managers with the situational awareness needed to make the intelligent life-or-death decisions required in such harrowing circumstances and to determine, as quickly as possible: (a) whether residents should in fact be told to evacuate; and (b) if so, in which direction and by which route or routes.

In short, the Ventura County Plume-Mapping Working Group now will be able, following a nuclear or chemical attack, to quicklyentify the direction of the plume and, working from that all-important starting point, to anticipate and greatly influence the direction of the evacuations needed. Surrounding counties can and should use the same information, of course, both to prepare for the evacuees and to ensure that incoming supplies and other tangible resources are redirected to the appropriate locations. Whatever the magnitude of such an event, the information provided by the Working Group immediately after a major chemical or nuclear attack will be critical in the decision-making process.

To briefly summarize: By creating a redundant group, under their own control, to map the course of the plume in the aftermath of a nuclear or chemical attack, emergency managers will be able, without having to depend on outside resources, to gather the critical information they will need to make their literally life-saving decisions. The same information also will help emergency managers determine the direction toward which residents should evacuate, and thus ensure that surrounding communities in the same geographic area are quickly and fully prepared to receive the influx of very large numbers of evacuees.


For additional information on: Similar incidents and detailed after-action reports, visit the Lessons Learned Information Sharing ( website at

The Ventura County Plume Mapping Working Group, visit Good Story, “Hazardous Materials Response: The Ventura County, California’s, Plume Mapping Working Group,” at

Omar Alkhalaf

Omar Alkhalaf, a contractor with SAIC, is an outreach and operations analyst for Lessons Learned Information Sharing (, the U.S. Department of Homeland Security/Federal Emergency Management Agency’s national online network of lessons learned, best practices, and innovative ideas for the nation’s homeland security and emergency management communities. He received a bachelor’s degree in Global Affairs with dual concentrations in Global Diplomacy and Governance/Middle East & North Africa Region from George Mason University in Northern Virginia.



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