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Action 6: Plan for a Phased Evacuation

Download full checklist (PDF) • See phased implementation plan

Develop planning strategies and logistical capabilities to support a large-scale, phased evacuation.

Evacuation professionals in the post–nuclear detonation context face a powerful dilemma. They are responsible for helping to relocate people who might otherwise succumb to acute radiation syndrome (ie, people in the least protective of shelters in the most radiation-intense sections of the DFZ23) or other life-threatening circumstances. Yet, these authorities must execute a large-scale, phased evacuation when the transportation and communication infrastructure is in disarray, when a potentially lethal and invisible hazard may be present, and when all survivors have the right to feel as if they deserve to leave first. Recognizing this complexity, this section outlines some preparedness steps that cities can take to improve the chances that, in an actual detonation, evacuation benefits those who most need it and adverse consequences are minimized. Carrying out a mass, phased evacuation in postdetonation conditions will be extremely challenging and contingent upon other capabilities such as rapid mapping of the DFZ. Preparing to execute this protective action is considered the most difficult implementation phase of the Fallout Preparedness Checklist. Comprehensive evacuation planning, according to federal policy, addresses the temporary resettlement of evacuees and the final return of evacuees to their predisaster residences or alternative locations.51 Preparedness for these activities is essential but is outside the scope of this document.


Task 6.1—Form regional partnerships and execute mutual aid agreements in support of mass evacuation.

Safe and proper evacuation of a large city requires regional support. Cities should form public health and emergency management partnerships with surrounding areas to address dilemmas posed by a nuclear detonation.

Pre-incident, this collaboration can be used to coordinate region-wide response, assess vulnerabilities, conduct training and exercises, plan for communication, and make modifications to existing mutual aid agreements if indicated. During and following a nuclear incident, the surrounding region can support evacuee movement, provide valuable reception sites to address evacuees with immediate health needs or chronic conditions, and facilitate state and federal assistance.52 Highly coordinated evacuations that include an effective command structure characterized by cooperation among all relevant agencies have been shown to be most effective.53

Task 6.2—Map out buildings and neighborhoods according to how they will perform as fallout shelters.

Rapid identification of people who could benefit from priority evacuation will be among the top response goals (see Tenet 4).5 Selection of priority evacuees can be expedited to save more lives by having already prepared jurisdiction maps to show neighborhoods and building clusters in terms of shelter quality.5 People in neighborhoods comprised largely of single-story, wood-frame houses, for instance, will be exposed to significantly more radiation than those who seek protection in the core of a large, multistory building. Prior knowledge of areas without adequate shelter options can also inform plans for designating public shelters in advance of a nuclear explosion (see Tenet 3).5 Planners should reach out to the private sector to access databases on area buildings, in addition to relying on data in the public domain. Similarly, emergency planners should identify clusters of children and disabled individuals (eg, nursing homes, hospitals, senior apartments) that may require additional assistance in evacuating.

Task 6.3—Predesignate the criteria against which some groups will be selectively evacuated early.

A difficult though vital preparation for a mass, phased evacuation is an agreed-upon framework among regional partners to guide the application of scarce resources in relocating people. Pre-established criteria about who will be evacuated first can help with tough choices in an actual postdetonation scenario, assure that the most lives are saved, and diminish adverse effects associated with mass evacuation. Federal guidance identifies the following life-threatening conditions as warranting early selective evacuation: inadequate shelter in the context of acute radiation exposure, fires and unstable physical structures, critical medical needs, and lack of life-sustaining resources such as water (especially after 24 hours).5 In an actual event, logistical matters such as safe evacuation routes will need to be considered. Mass evacuation can be an extreme solution with many serious consequences. Potential adverse effects include psychological impacts, social distress, and income interruption.54

Officials should therefore reserve its use for life-threatening circumstances or other exceptional circumstances where the benefits clearly outweigh risks.

Task 6.4—Consider how preestablished evacuation routes and transportation options may have to be adapted to the nuclear detonation context.

Predetermined evacuation routes and transportation options that assume an intact infrastructure and a nonradiological hazard, such as a hurricane, would need substantial revision in the context of a fallout plume and blast- and EMP-related damages (eg, debris-strewn roadways, overturned vehicles, no power for traffic signals, loss of public transportation). Comparing preestablished evacuation routes against different fallout plume projections and models of variously damaged infrastructure (eg, certain bridges are out) can provide planners with advance understanding of some of the challenges of moving large groups to safety following a nuclear attack.5 As part of a pre-incident public education campaign, explaining the uncertainties anticipated with a postdetonation evacuation may help reinforce the message that staying inside an adequate shelter and waiting for more information, rather than automatically leaving an area, is the more desirable protective action.

Task 6.5—Craft pre-incident public education materials that share evacuation plans.

Evacuations are more likely to be successful when officials have shared plans with the community in advance and explained alerting methods.53

Pre-incident public education materials should convey when leaving a shelter is appropriate, what relocation plans exist, and how officials will communicate postdetonation. During a mass, phased evacuation, people in different locations will be asked to take different protective actions (“continue to shelter” versus “now evacuate”). Therefore, as part of pre-incident public education, planners should consider preparing diagrams, similar to those that would be used in an actual emergency, that represent different phases of an evacuation. Diagrams will be a critical communication tool in an actual warning scenario; introducing these images pre-incident can help familiarize residents with a phased evacuation process. While some people may not have access to such diagrams during the actual emergency, people in outlying regions where communications are still functioning will be prepared both to see and hear the message that they may be in areas that do NOT need to evacuate.

Some experts caution that raising the prospect of an informed evacuation in advance may confuse people about the principal importance of sheltering. In an actual incident, such confusion might predispose people to leave an area before there is sufficient information on safe evacuation routes or when evacuation is unwarranted because of low radiation levels. Public safety educators should strive to strike a balance between conveying the benefits of sheltering and adequately preparing residents for a phased evacuation.

To balance potentially inconsistent messages about continuing to shelter and preparing to evacuate, public messages might be framed as, “Stay inside an adequate shelter until you receive additional information.”

Task 6.6—Prepare scientifically based templates for postdetonation evacuation messaging.

Preparing evacuation messages in advance can expedite their timely release in an incident and minimize radiation-related illness and death. Effective messaging (such as that modeled in Formula for Writing an Effective Message for Postdetonation Public Warning) helps ensure that only those who should evacuate do. An informed evacuation implies that a person understands both when to leave a shelter and in which direction he or she should go to minimize exposure to radioactive fallout and other hazards.55 Evacuation messages should provide detailed evacuation instructions, including evacuation zones, plans, routes, and/or decontamination centers, as well as specific times and arrangements for certain neighborhoods.56 Messages should also clearly state that certain areas do NOT need to evacuate and that unnecessarily leaving an area could jeopardize others by clogging evacuation routes. Evacuees should understand that they will need to evacuate from their place of shelter and that they may not have an opportunity to go home or reunite with their family first.

Task 6.7—Anticipate that a portion of residents will evacuate independent of government instruction.

Following a nuclear detonation, some people will attempt to escape real and perceived dangers independent of official recommendations and radiation data. Regional evacuation planning should prepare receiving communities for the challenges these self-evacuees may pose. Individuals who spontaneously evacuate a fallout area prior to receiving official instructions may have greater decontamination needs when compared to people who stay in adequate shelter before evacuating.57 Any large-scale evacuation is also likely to have a high rate of shadow evacuation58—that is, departure from areas not officially designated for relocation. After a nuclear detonation, the total evacuee population will likely include injured and noninjured individuals who have been relocated from at-risk fallout areas, plus a potentially large number of shadow evacuees. For example, New York City expects to have to evacuate 300,000 people for health reasons. Yet, receiving communities may also have to face many times that number of uninjured evacuees who still need food, shelter, and medical care for their chronic conditions.58 Out of concern about possible radiation exposure, many spontaneous and shadow evacuees will likely self-report to hospitals in receiving communities.

Task 6.8—Plan to establish monitoring and decontamination centers (ie, community reception centers) for people leaving affected areas and moving to host communities.

Given radiation’s health effects as well as an ability to evoke fear sometimes out of proportion to risk, a nuclear detonation will produce high demand for monitoring of exposure to or contamination from radioactive materials. The Centers for Disease Control and Prevention (CDC), in collaboration with many other partners, has produced a guide for state and local public health planners on establishing a system for population monitoring, a core of which is the community reception center (CRC).35

The purpose of the CRC—which may be co-located with other disaster resource sites such as alternative care treatment sites or shelters operated by the American Red Cross—is to assess people for exposure, contamination, and the need for decontamination or medical follow-up. CRCs will play a key role in protecting the public health of people from affected areas and alleviating the anxiety of communities taking in evacuees. Planners should note, however, that past evacuation experience indicates that when people evacuate, they often scatter to nearby friends and family; therefore, not all evacuees will report to a designated shelter or, in this case, a CRC.