Sunday, 18 May 2008

The Use of Scenarios for Emergency Training

Figure: Scenario methodology for emergency planning.

The idea that crisis situations are unique and unpredictable is a misleading truism. In fact, emergencies are made up of both foreseeable and unexpected elements. The way to manage them is to anticipating the former in order to minimise the latter. This can be achieved by building predictive models, or scenarios, of what is likely to happen in the future.

The models are a vital ingredient of both planning and training. In an emergency plan the reference scenarios can be taken from significant events that have occurred in the past, which must be updated to take account of modern conditions. The scenario can be elaborated in terms of hazard, vulnerability, impact and emergency response. A systems methodology should be used for this (see Figure) and the conditions tailored to a variety of situations, for example with respect to disasters that strike at night or during the day, the outcomes of which are, of course, related to aggregate patterns of human behaviour. As the essence of emergency planning is to anticipate pressing needs in order to supply them effectively at the critical moment, a well-constructed set of crisis or disaster scenarios is an essential aid. Coupled with an audit of emergency resources (vehicles, equipment, supplies, manpower, procedures and protocols) the scenario can help identify potential shortages and deficiencies so that these can be corrected before the next disaster strikes.

The other main use of scenarios is in training. As the field of emergency management becomes steadily more professional, course leaders must consider the problem of how to make training lively, realistic and relevant to actual crises. Scenarios can be used to provide a means of getting students to think their way into emergency situations. The scenarios should be chosen carefully, or synthesized from the most relevant events, and should be used with care in order to teach essential principles.

A training scenario example

By way of example, the following scenario, given in abbreviated form, was originally posted to an Internet search and rescue discussion group on 18 March 1996. The story has been modified to make it brief, generic and illustrative of the dilemmas that face the emergency manager in the field. Students or trainees are asked to consider how the emergency is developing, devise a strategy for co-ordinating the relief effort as it gets underway and consider the limitations to what can be achieved.

On the periphery of a large industrial city a factory that once produced vehicle batteries is about to be rebuilt into a wholesale warehouse. Inside it there are some large, rusting tanks that contain residues contaminated with arsenic and cyanide which are leaking slowly into the ground beneath. The roof of the factory, which workmen have begun to dismantle, contains asbestos.

Wood and aluminium scaffolding has been erected up to roof level and polyethylene sheeting has been rolled out to contain the asbestos dust. As it is winter, space heaters powered by bottled liquid propane gas are being used inside the building. Electrical power is obtained exclusively from a connection point at the perimeter of the site which is next to a storage area containing a large number of LPG canisters.

During the lunch-break there is a violent storm with heavy gusts of wind. Part of the scaffolding collapses and the polyethylene sheeting catches fire when it comes into contact with one of the space heaters. A large explosion leads to a fierce fire that generates temperatures of more than 1000EC. The building is rapidly consumed by flames, which burn out the site office and then move toward the LPG storage area. The site office and electricity point are destroyed.

The flames reach the gas canisters and the resulting explosion seriously damages the water supply hydrant and the drains, such that the toxic materials stored on site start to leak copiously into the sewerage system. Above the burning factory a cloud forms, rich in the combustion products of the toxic substances present at the site. The wind is blowing it gently towards a school, which is occupied, and an area of housing.

Within minutes you arrive at the site, the first incident commander to reach it. How are you going to manage the situation? What resources will you need and what can you count upon obtaining quickly?

Classroom strategies

Experience in the classroom with a wide diversity of student and trainee groups suggests that the discussants usually fall into two categories: those who are practical by nature and those who have yet to grasp the difference between what can be done and what cannot. To manage the emergency well, they must divest themselves of the purely academic approach. For example, there is no time to analyse the toxicity of the smoke, to measure wind speed or even to evacuate the school and the residential area. A warning can only be given if there is a safe way of delivering it, and the best strategy is probably to use a police car with loudspeaker and a series of telephone calls advising people to stay indoors with windows and doors closed. The first priority should be to warn the school.

With a little gentle persuasion, students can be encouraged to think realistically in operational terms, listing first the problems to be solved, secondly the needs that they generate and thirdly how to manage them by applying some simple rules.

The problems can be summarised as follows:-

- a high-temperature fire
- explosion damage and a continuing hazard
- the toxic cloud
- potentially severe pollution of the storm drainage system
- toxic substances at site (asbestos, cyanide, arsenic, etc.)

The principal needs generated by the emergency are:-

- evacuate the factory site and protect people against fire and explosion hazard
- protect residents and people in the school from the effects of the toxic cloud
- contain the fire and abate of the explosion hazard
- protect the sewerage system and limit toxic contamination

These are the possible operational strategies for devising solutions:-

- distinguish, list and prioritise tasks (it should become second nature to do this)
- where appropriate, delegate responsibility
- do not tackle problems that lack an immediate solution
- where it can be done, apply a workable solution

For example, five questions come to mind regarding the toxic cloud:-

- can a rapid estimate be made of where it is going and roughly how fast?
- where will it get to and approximately when?
- how much time is there in which to do something?
- what emergency resources are likely to be available in that time interval?
- under the circumstances, what would the most appropriate strategy be to limit the cloud's effects?


As it is not so much the seriousness of the problem that counts but the efficacy of the solution, what is needed is a form of mental triage. The 'golden rules' for applying this are three. First, all solutions must function in the very short term. Secondly, it pays to limit one's span of control, where appropriate by delegating responsibility for specific tasks (calling the HazMat team, for example, and explaining the situation to its leader). Thirdly, problems should be judged by the likelihood of achieving a solution quickly with the available means. If this cannot be accomplished a problem should be delegated or deferred in favour of more solvable matters.

For many students who are new to the field of emergency management, a classroom scenario such as the one described may be their first introduction to the concept of operability. They need to accustom themselves to working in an environment of great uncertainty, and hence one of the greatest challenges for the teacher is to reduce the role of hindsight and encourage the trainees to think themselves into the emergency situation, dealing with information as it arrives, when it is in short supply relative to what needs to be known and has yet to be verified.

The scenario listed above is an extremely basic one which has been cast in a generic form--i.e. without reference to any specific system of command and control or particular set of operating rules. These can, of course, be added in order to lend realism, but a balance must be struck between adding operational detail and obscuring the general picture

In synthesis, scenarios are both a fundamental input to emergency plans and a vital teaching resource. With a little thought and the distillation of field experience, what would otherwise be a mere anecdote can be turned into a useful tool for illustrating the basic principles of emergency management.

Further reading

Alexander, DE (2000) Scenario methodology for teaching principles of emergency management. Disaster Prevention and Management 9(2):89-97.

Janing J (1997) Assessment of a scenario-based approach to facilitating critical thinking among paramedic students. Prehospital and Disaster Medicine 12:215-221.

Ringland, G (1998) Scenario Planning: Managing for the Future. Wiley, New York.

Walker, WE (1995) The Use of Scenarios and Gaming in Crisis Management Planning and Training. Rand Corporation, Santa Monica, California.

This article is reproduced with permission from:-

Alexander, D.E. 2005. Use of Scenarios for emergency training. Chemical Hazards and Poisons Report 5, UK Health Protection Agency, London: 24-25.