Ashraf instrumental in establishing guidelines for new world weather extreme records


In 2015 Dr Ashraf Dewan accepted an invitation to be a member of the World Meteorological Organization (WMO) Commission for Climatology (CCl) ad-hoc Weather and Climate Extremes evaluation committee for weather mortality extremes.

This committee was empanelled to evaluate the data associated with five new potential world weather extremes:

  1. Deadliest tropical cyclone,
  2. Deadliest tornado,
  3. Deadliest hailstorm,
  4. Deadliest lightning strike (direct death),
  5. Deadliest lightning strike (indirect death).

As these were five new world weather extreme categories, there were no previous record events established for these five WMO extremes.  Consequently, the committee’s work was to establish the precedent-setting guidelines for these extremes.

Panel members were selected for a range of specific expertise including local climate knowledge, understanding of factors contributing to an extreme occurring at a particular location or specific climate phenomena for the world in general.

The committee summarised their research in a paper in May of this year with the findings as below.

  1. Deadliest tropical cyclone:  the Bangladesh Cyclone of 12-13 November 1970 (commonly known as the ‘Great Bhola Cyclone’) with an estimated 300,000 (low end) to 500,000 (high end) storm-related fatalities (mostly the result of a 40 foot storm surge overwhelming the islands and tidal flats along the shores of the Bay of Bengal).
  2. Deadliest tornado:  Manikganj district, Bangladesh [23°50’N, 90°5’E, elevation: 9 metres (30 ft)].  Tornado occurred on 26 April 1989 with an estimated death toll of 1,300. The towns of Saturia and Manikgank Sadar were destroyed. This violent storm injured over 12,000 and left over 80,000 people homeless.
  3. Deadliest hailstorm:  Occurring near Moradabad, India on 30 April 1888, this hail event is said to have killed as many as 246 people.  Reports state that hailstones as large as “Goose eggs and oranges” fell.
  4. Deadliest Lightning Strike (direct death):  near Umtali, Rhodesia (now Mutare, Zimbabwe) on 23 December 1975 when 21 people inside a hut were killed by a single bolt.
  5. Deadliest Lightning Strike (indirect death):  Brescia Italy, 18 August 1769.   A bolt of lightning struck the 80-foot stone tower (St. Nazaire) build into the medieval defensive walls around the town of Brescia, Italy.  The tower also served as the town’s gun powder magazine and contained 78 tons of black powder.

In their report, the evaluation committee stated “These mortality extremes serve to further atmospheric science by giving baseline mortality values for comparison to future weather-related catastrophes and also allow for adjudication of new meteorological information as it becomes available.” For the first time in its history, the World Meteorological Organization released these world records of the human toll from these extreme weather events, and the issue received worldwide media coverage. Previously, the official WMO Archive of Weather and Climate Extremes kept only temperature and weather records to address the impacts of specific events.