Extreme weather events – We are forewarned!
We are forewarned!
Dr R Neerunjun Gopee
Since the beginning of the week walkers at Trou-0-Cerfs have noticed that the fencing that was erected on a length of the road leading to the radar which was undergoing construction is being gradually removed. We have also seen what we can call the completion works at the radar site: scaffolding used for painting has been removed, the yard has been laid out, the gate installed with a guard post adjoining it, the signage ‘Mauritius Meteorological Services’ put up in golden letters, and generally all the signs of readiness are present. Which leads us to assume that the inauguration is due shortly, since it had initially been announced for October and there’s this delay.
We are therefore impatient – since we are the citizens who have directly witnessed the tower rising to its present magnificent state from Day One nearly two years ago now –, like all our fellow Mauritians, to see the radar becoming operational, as the Meteorological Services have already announced, or warned rather, that we are in for quite disruptive weather conditions this summer season. We are only just at its beginning, and already there are some worrying indications of what awaits us. Thus, we have got off to a rather dry start and some quite uncomfortable hot days, with little breeze, which makes for a stifling feeling especially at night, often causing restless sleep.
Ah! As I am writing now at midday (Tuesday last), there’s a welcome downpour. It’s not too heavy but good enough to begin taking the heat away; don’t know how long it will last, but hopefully longer rather than shorter! Nevertheless, it is a relief because on Monday too, the sky was overcast but finally there was only disappointment and no rain.
Checking the Met Services, I read that ‘the airstream remains light, warm and rather unstable over our region’ and that the forecast for the next 24 hours is ‘cloudy over the major part of the island with local showers. The showers will be moderate at times and could be accompanied by isolated thunderstorms…’
A little relieved that since it was going to be Divali the next day, we would be spared of rain, but I certainly pray with others that the skies will become more generous with our island very soon. Water cuts have begun, and the water levels in all reservoirs are already reported to be less than the optimal for this time of the year compared to last year.
The Met Services have informed us that we can expect much hotter spells this summer, with cyclones as is usually the case, but that there is an enhanced possibility of heavy rains and flooding, including flash floods, and thunderstorms. The new radar will no doubt add to our capabilities in this sector.
The uncertain science of forecasting
As in all sciences, there have been tremendous advances made in meteorology too, but the more we know the more questions arise, revealing the greater extent of our ignorance. If ignorance is a circle with knowledge at its centre, every addition of knowledge makes the centre shift and the circle grow bigger – and that’s why we end up with more questions than answers.
So it is on the basis of such limited knowledge that we try to negotiate through the problems that life throws at us. In several situations, we have to make estimates which, depending on the discipline, can be more possibilities than probabilities. This appears to me to be the case with meteorology which, like the biological sciences with which I am more familiar, has among the variables it deals with more ‘unknown unknowns’, making forecasting an uncertain science. There is another fundamental idea, drawn from quantum mechanics, which resonates here – the uncertainty principle of Heisenberg, which is the concept that precise, simultaneous measurement of some complementary variables – such as the position and momentum of a subatomic particle – is impossible. I am almost sure that there must be, in meteorology, complementary variables too.
Like everybody, I was traumatized by the flash floods that occurred in Port Louis a few years ago. Firstly, it was a new phenomenon in our climate landscape, with the death of several people. Secondly, it led to the exit of the Director of Meteorological Services.
I do not know the exact circumstances of his departure, but as a former civil servant myself I could not help reflecting on the vulnerability of those who occupy high posts, including technical positions. Not infrequently, they unwittingly become the victims of populist pressure fuelled by ignorance and baying for blood, combined with scapegoating as the easy way out for an establishment too impatient to be properly informed about the technicalities let alone the complexities involved.
In their case, the rule of law that one is innocent until proved guilty is turned upside down to ‘guilty until proved innocent?’ – which can take years and meanwhile s/he’s been hounded out!
As a layman with a science background, I researched a little about the phenomenon of flash floods. I had known fairly well two former directors of the Met Services and was interested in weather phenomena since my Boy Scout days when we were initiated into its rudiments.
I came across two papers: 1. Quarterly Journal of the Royal Meteorological Society ‘Flash flood forecasting: What are the limits of predictability?’ (italics added) 2. ‘Flash Floods: The Role of Science, Forecasting, and Communications in Reducing Loss of Life and Economic Disruptions – An Information Statement’ of the American Meteorological Society (Adopted by AMS Council on 17 April 2017) – and other information available online, which give a better understanding and appreciation of the complex issues which make decision making extremely difficult.
A flash flood is defined as ‘Flooding caused by rapidly rising water level in streams… or other waterways, …or in urban areas, usually as a result of intense rainfall over a relatively small area or for moderate to intense rainfall over highly saturated or impervious land surfaces, and generally occurring within minutes to several hours of the rainfall event’, with the ‘rapid occurrence resulting in a very limited opportunity for warnings to be prepared and issued’. Further, ‘flooding may be intensified by changes of land use which increase the rate and volume of runoff…’
‘Rainfall from the storm over an urban area will cause flooding faster and more severe than in the suburbs or countryside. The impervious surfaces in the urban areas do not allow water to infiltrate the ground, and the water runs off to low spots very quickly’.
What are Port Louis and Caudan but impervious land surfaces due to changes of land use and, further, low lying coastal areas which would increase the rate and volume of runoff…’?
‘Forecasting the time and location of flash floods requires high-resolution modelling of weather and water, assimilation of large data sets from high-resolution observations, and an integrated, coherent approach that allows meteorologists and hydrologists to make rapid assessments and warning decisions’ – were the Met and hydrological services in such an ‘integrated, coherent mode’ and did they have the latest in technology platforms to collect and process data?
More telling is the observation that ‘it would be over optimistic to expect the reliable spatially accurate quantitative prediction of flash floods to extend beyond 1 or 2 hours ahead within the next 10 years’.
But in blessed Mauritius, some ignoramuses are ‘plus royaliste que le roi’!
Social awareness and sense of self-responsibility
Which brings us to the issue of preparedness and coping with these extreme weather situations. We already have a well-honed protocol for cyclones, which combines accurate forecasting with national logistics in place, and social awareness that has been strongly inculcated into citizens so that they pay heed to warnings and take all the advance precautions advised in terms of housing and food security during that period.
Given the forewarning by the Met Services, it is perhaps advisable for people living in flood prone areas to similarly begin planning some measures in case of the event, and for the national authorities to provide some guidance in this regard.
This would also apply to so-called ‘refugees’ who should rather be designated as Persons in Temporary Shelters (PTS) because they do not conform to the UN definition of a refugee as ‘someone who has been forced to flee his or her country because of persecution, war, or violence. A refugee has a well-founded fear of persecution for reasons of race, religion, nationality, political opinion or membership in a particular social group. Most likely, they cannot return home or are afraid to do so’- which is clearly not their case in this country. There is no war or persecution going on; in fact it’s quite the opposite, with the State arranging for appropriate shelter, and providing assistance with transport and food, and offering a voucher.
Further, it would be recalled that during cyclone Berguitta in January this year, the UNHCR (the UN Refugee Agency) calorie recommendations had been evoked concerning the supply of food items to cyclone ‘refugees’. We had then pointed out that ‘from a medical point of view a calorie restriction during a couple of days (which means maybe 6-8 meals) will have no significant effect on the individual. These kinds of calculations apply to, once again, true refugees who are fleeing and who have already been undergoing prior deprivation. In a cyclone emergency situation like ours with PTS stays of 48-72 hours, the priority is to assuage hunger, not nutritional issues. More so because regular nutritional surveys in Mauritius have never shown any deprivation, and so for normal persons like the PTS in Mauritius it is only after about one week that such considerations would begin to apply. But we know that the PTS never stay that long. And as others have pointed out, there are resquilleurs (cheaters who take advantage of the situation) among the PTS’.
And also that, ‘given that the meteorological station gives sufficient advance warning of an impending cyclone, advising people to stock up, there is nothing that prevents potential PTS to do the same within their means and eventually carry their goods with them. This applies especially to parents with babies who are best fed on their own milk brand (unless they are being breast fed)’.
Moreover, ‘on a humanitarian ground if it is possible under the dire conditions of Class 3 cyclone, the country – and that means the Government, Civil Society and the Private Sector — should certainly try to provide hot meals to these fellow compatriots, or to arrange for their preparation by the PTS themselves through cooking arrangements organized at the shelter’.
And our final remark post Berguitta is still relevant: ‘We have the experience and the capacity to handle cyclonic and post-cyclonic situations. What we must do is to continuously strengthen these capacities and address the gaps and weaknesses, such as the drainage and agriculture issues, with a greater degree of urgency than we have perhaps done so far. Complacency must not be allowed to set in’.
* Published in print edition on 9 November 2018
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