Cyclones: Finally a natural
disaster which Bangladesh is not only familiar with but also somewhat PREPARED
FOR. In case you missed the last episodes, Bangladesh should not be on your top
ten places to live list. It turns out that Bangladesh does not have any of its
own satellites and it relies on the NOAA and NASA satellites which send data
remotely to the Bangladesh Space Research and Remote Sensing Organization, which
is part of the Ministry of Defense. Apparently SPARRSO has a detailed “storm
prevention” strategy (I think this is simply a poor choice of semantics on
their part but it makes for rather amusing brain fodder to imagine a group of
wizards at the ministry of defense combining their power to stave off the
forces of nature). All joking aside, they have a volunteer force of
approximately 32,000 people who are trained to warn and evacuate citizens
especially in lower coastal areas and a network of 2,500 cyclone shelters. Petenga
and Chittagong have built sturdy concrete levees to protect that part of the
coast. After reading about how cyclones affect Bangladesh, I can see why they
do not spend much time or money (comparatively) on earthquake or even
subsidence mitigation. The Bhola Cyclone in 1970 killed 500,000 people (and that
statistic is likely to be conservative). Over one million cattle were killed,
20,000 fishing vessels, 400,000 houses and 3,500 educational institutions were
also destroyed. The wind during the Bhola Cyclone reached a maximum of 222km/hr
and the maximum sure was over 10 meters. Bangladesh suffers primarily from
tropical cyclones. They can last up to 24hrs and they produce a huge amount of heart and moisture. They
knock out power and contaminate what few potable water supplies Bangladesh has.
In a country as heavily populated as Bangladesh, a power blackout could be
devastating in itself as it would put hospital equipment out of commission and probably
slow down the warning and guiding systems necessary to reach as many people as
possible in a disaster. http://en.wikipedia.org/wiki/List_of_Bangladesh_tropical_cyclones
In April of 1991 another massive cyclone hit the coast of
Bangladesh. It is now known as the Bangladesh Cyclone. It killed approximately
15,000 people which is a lower death toll than the one recorded in the Bhola
Cyclone but I believe this was due to the country’s mitigation techniques
having improved since the 70’s. Still, many died because they refused to
evacuate, believe the intensity of the storm to be less than forecasted. The Max
wind speed was 260km/hr which was measured for a minute at a time. This is the
timing scale Bangladesh uses to measure wind speed as opposed to being measured
over a 3 minute period which is what most countries use. What is surprising about cyclone death tolls
in the area are the number of people who die from drowning. Most of the deaths
in the Bangladesh cyclone of 1991 were drowning victims. This boggles my mind
because I can see disease and water contamination as well as insufficient
shelter being the cause of so many deaths but for some reason it is too surreal
for me to comprehend. http://en.wikipedia.org/wiki/1991_Bangladesh_cyclone
The initial dome of water which makes landfall is called the storm surge and it
is caused by a combination of the hurricane’s winds and ocean surface which
form not so much a tidal wave as a mountain of water to rise and then collapse
on shore. 90% of the deaths in cyclone
in Bangladesh are caused by the storm surge. The storm surges in Bangladesh are
particularly deadly because the water nearest the coast is relatively shallow
which means the surge does not have the depth or breadth of ocean space to
disperse and loose energy. These surges can travel inland as far as 25miles and
there is no method of prevention so the only mitigation option is to evacuate
to a higher elevation.
Interestingly, although Bangladesh does utilize the
hurricane rating system with the intensity scale of 1-5, it also rates its
tropical storms on a scale of 10 to measure destruction.
Along with the initial storm surge there is of course
torrential rainfall during a hurricane and this rain causes flooding and
landslides which also claim property and lives.
In 2008 Tropical Cyclone Nargis hit Mayanmar, Bangladesh,
India and Sri Lanka with winds reaching 215 km/hr (on the one minute time scale
mentioned above). The total death toll was approximately 138,000 people. Only
3,500 of those were in Bangladesh. It was one of the most destructive cyclones
in the history of the area, causing approximately 10 billion dollars in damage
throughout all 4 countries. Yet, it seems as though Bangladesh is doing quite
well for itself in regards to the road to Cyclone disaster prevention.
