On April 14, a severe flash flood invaded Oman from an extreme precipitation event that lasted until April 17. The highest rainfall record over the entire period was 302mm, while the peak hourly record reached 180.2mm. This weather event is not an extraordinary case considering the topography of Oman represented by the lofty Al Hajar mountains. Advection from hot and cold air masses during this transitional season and moisture flow from the surrounding water basins are all a recipe for severe thunderstorms, especially when combined with an external trigger such as surface low pressures and extended upper level-troughs. However, the interaction of humans with natural hazards created susceptibility to a disaster. Up to April 18, 21 people were found dead, including 11 pupils and infants. The final number of lost bodies is not yet confirmed. At least 1200 people including kids were trapped in schools and buses rescued by the Civil defence. Many people were isolated on the road or in their houses as flash floods invaded their homes and gardens, cutting off transportation links.

The loss was tremendous despite the issuance of warnings and forecasts. The root cause of this disaster was inadequate decision-making which led to the loss of life and enormous damages by increasing the risks, exposure, and vulnerability. Communities live on the floodplain and the flood-prone areas in the valleys (locally known as Wadis) that connect the mountains and the coastal plain. Intensive floodplain land use and a poor urban planning system aggravated flooding incidence. However, no statistics are available to the public indicating the extent and nature of property damage. The absence of a sufficient drainage system amplified the calamity during this case due to the saturation and flooding of the ground from the persistent precipitation.

Are we prepared for more extreme precipitation and intense tropical cyclones in the future as a consequence of climate hazards and cloud seedings operations? How can we mitigate and reduce the risks from extreme future scenarios when the precipitation record is broken?

Call for Action

Day and Fearnley (2015) divided mitigation systems into three main strategies based on when and how actions should be taken: permanent mitigation, responsive mitigation, and anticipatory mitigation. Their study showed how important it is to integrate and coordinate these three strategies, which also need to be tested to see how well and resilient they work. For these strategies to work well together, paying close attention to how they affect each other is essential. The most important thing to consider is how the vulnerable population understands the decision-making processes, how they react to the warning messages regarding their awareness, and what they expect these strategies to do. For example, the limited ability of permanent mitigation strategies to deal with rare hazards under poor responsive and anticipatory strategies leads to disastrous results. The historical record was ignored during the northeast Japan earthquake and tsunami on March 11, 2011, despite the high standards of permanent mitigation measures. The same thing could happen under irresponsive actions toward the issued warnings. The schools and workplaces would have been moved online, and the announcement should have been made at least 48 hours before the approach of the significant weather cases.

Successful mitigation systems require four key components: a map of the hazards, an early warning system, a control structure and non-structure measures, and regional planning and development (Wieczorek et al., 2001; Larsen, 2008). Non-structural measures can include reorganising, removing, converting, discouraging, and regulating growth (Wieczorek et al., 2001). For example, preventing, and minimising the redevelopment of areas susceptible to the future hazards. Hazard-prone areas can be utilised as an open space or certain type of farming taking in consideration the relevant factors.

A structural measure could include designing and constructing parallel to the flow direction and constructing multi-story buildings where the second floor can be used for living instead of the first (Kelman, 2001). Unfortunately, no public building census data is available to determine the number of stories in existing buildings in Oman. Other engineering solutions, such as large debris flow impoundment dams and their regular maintenance, could offer some protection even for the alluvial fan regions. More research must be conducted in each watershed to answer specific design questions, including the size of the event for which they should be built (Larsen, 2008).

Although the warning system does not prevent property damage, it protects lives by predicting flood-prone areas. It relies on radar, ground, and upper-air observations, as well as a robust model to identify the thresholds that trigger flood risk for each place with a rapid and practical link between Ministries of education, higher education, labour, civil defence, police, and the relevant authorities. Using general flash flood forecasts for fear of false alarms reduces the credibility and practicability of the warning system. On the other hand, the use and value of a warning are inversely proportional to the size of the geographical area covered by the warning (Larsen, 2008).

Regional planning and policy formulation need to involve multidisciplinary experts. For example, developing a flood hazard management policy requires technical expertise, public education and awareness, and good communication between scientists, policymakers, and politicians. Local communities should be involved alongside physical and social scientists. Post-event decision-making about recovery and reconstruction involves an exemplary dialogue between the government, experts, and the local population. Different options must be considered, such as balancing flood risk reduction against loss of livelihood and social considerations, and a compromise must be reached between the different groups. This measure guarantees that local voices and narratives are heard, ensuring resilience can only be accomplished by appreciating human livelihoods. 

With the increasing responsibilities and capability of efficiently responding to warnings, the study of how decision-makers and people receive and react to a warning has become essential to warning design. Educational programmes should be developed to increase familiarity with the warnings and the appropriate response (see Towards the “perfect” weather warning from the WMO), which is also emphasised in Target G of the Sendai Framework to “Substantially increase the availability of and access to multi-hazard early warning systems and disaster risk information and assessments to people by 2030”.

There is a need to develop disaster risk reduction strategies and systems that allow for the large uncertainties in the region’s hazard frequency-intensity distributions. No one can deny the complexity of Oman’s topography or the flood risks in the Al Hajar mountains, but this topography can be a boon if properly engineered and utilised.

Finally, a comprehensive national flood hazard management strategy is urgently required, along with urgent actions to be implemented to tackle the cascading flood risks. With each further delay, the total cost of the bills will go up even further in the future.

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Salma Al-Zadjali is a PhD candidate at IRDR, researching decadal climate variability of precipitation in order to assess the feasibility of a cloud seeding project over the Al-Hajar mountains in Oman. 

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The views expressed in this blog are those of the author.

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Written by Professor David Alexander

I have been speaking widely on the COVID-19 crisis on television, radio and podcasts, and in newspaper and magazine articles. As my main speciality is emergency planning and management, most of my comments have dealt with this field. I first came into contact with the scenario for a major 21st-century global pandemic in 2008. This was the collective result of an initiative launched in the mid-2000s by the World Health Organisation to provide a global response plan and encourage individual countries to prepare. Influenza was most feared, thanks to an on-going re-evaluation of the pandemic of 1918-1920 (which killed between 50 and 100 million people). However, the response to SARS in 2003 showed that concerted international action might be necessary to counter a lethal, infectious disease that was not a strain of influenza, and so it has proven.

In essence, emergency management is composed of three elements: plans, procedures and improvisation. The plans orchestrate the procedures, and both should reduce improvisation to a necessary minimum by foreseeing needs and designating means of fulfilling them. Failure to constrain improvisation in this way could be regarded as negligence.

In COVID-19 we see many examples of frantic improvisation as countries, including the United Kingdom, scramble to procure personal protective equipment, ventilators, respirators and so on, and as they hastily create and arrange the policing of social distancing measures. Adaptive management is practised, but not in the spirit in which it was invented (as a means of improving the efficiency of direction), but as a breathless attempt to keep up with a scenario that has not been read, interpreted and turned into preparations.

Although the broad scenario has been with us for between ten and 15 years, many of the details were either neglected or simply did not rise to prominence until the pandemic actually struck. These include the plight of people on large ships or in prisons, both places of confinement. Then there are, very significantly, the arrangements for supporting care homes for the elderly. In some places, more than half of the mortality from COVID-19 apparently occurs in such places, but they have not received the same level of support as have the hospitals and clinics, nor have they always been monitored or properly regulated. Thirdly, the role of social media and mass media in spreading misleading information, conspiracy theories and fantasies needs to be considered. Many people follow celebrities and a number of these have aided the spread of false information, which has led, for example, to multiple attacks on cellular masts under the fallacious assumption that 5G telephony causes the spread of the virus.

I have begun a COVID-19 observatory. This is simply a means of collecting information and classifying it. Because we live in a networked, highly interdependent world, modern disasters are cascading events in which chains and webs of causality occur. Pandemics are recurrent, and we need to refine the basic planning scenario for dealing with them at scales that extend from local to global. We also need to consider how to manage the later stages of the present crisis, and any resurgence of COVID-19 that may occur after the current wave. Information needs to be collected because much of it is ‘perishable’, which means that it is liable to disappear with time if not identified and recorded. It then needs to be classified so that the nature and connections of the cascade can be understood.

Emergency planning needs to be holistic and responsive. A plan should be a ‘living document’ which is constantly refined, updated and made known to its potential users. This gives the opportunity to broaden its scope and tackle previously neglected issues, such as the three outlined above. In emergency planning, experience is a great teacher, and it needs to be married with a systematic, logical approach to the rational use of available resources. These are all good justifications for studying cascades. Hence, at UCL-IRDR, we have a Cascading Disasters Research Group, which produces theory, applications and analyses of practical examples.

I will be pleased to hear from anyone who would like to contribute to the COVID-19 observatory. The results of the exercise will eventually be shared in order to help everyone gain a deeper understanding of what is going on.

Prof. David Alexander

david.alexander@ucl.ac.uk