©  Marco  Pluijm    08/03/2017    

                                         

©  Express  

Weather Bombs as Impact Parameter  Marco Pluijm M.Sc. Innovator and Seasoned Professional  Weather  bombs  are  hot.   Judging  the  number  of  articles   in  the  media  about  this  phenomenon,   one   could   conclude   that   they   are   increasing   in   frequency   of  occurrence  and  intensity.    What  some  articles  also  tell  us  is  that  not  all  weather  bombs  actually  deserve  that  qualification.    It’s  also  the  new  media  who  seem  to  love   the   typecasting  as  a  part  of   their  headlines.   It  attracts  attention  and  so  do  the  spectacular  pictures  that  often  come  with  it      The   formal   definition   of   a   “weather   bomb”   is   a   type   of   extratropical   cyclone,  characterized  by  a  low  pressure  system  in  which  the  central  barometric  pressure  drops  at  least  24  millibar  in  24  hours.      Weather   bombs   come   with   hurricane-­‐force   winds,   massive   waves,   extreme  downpour   or   very   heavy   snowfall.   Records   show   average   waves   of   14   to   15  meters  high  along  the  UK  West  Coast,  with  in  there  much  larger  extremes.      Based   on   a   global   30-­‐year   dataset,   it   is   estimated   that   every   year   there   are  between   45   and   65   of   these   explosive   events   across   the   world,   mainly   in   the  northern  hemisphere.    The   actual   number   is   thought   to   be   much   higher   and   hard   to   predict   due   to  significant  gaps  in  the  global  observation  networks.    Which  also  makes  that  their  trend  in  terms  of  frequency  and  intensity  is  equal  debatable.      

©  Marco  Pluijm    08/03/2017    

However,   linking   weather   bombs   with   the   increased   activity   of   hurricanes,  provides  a  hypothesis  of  similar  growth  of  frequency  and  activity.  Regardless  the  actual   number,   given   their   presence,   relative   short   duration   and   recorded  massive  impact  forces,  weather  bombs  shall  be  taken  into  account  as  an  integral  part  of  accelerated  climate  change.    Which  brings   them   in   the   same   category  as  hurricanes,     storm  surges,     etc.  All  extreme   wather   impact   impact   phenomena   which   do   not   seem   to   follow  traditional   patterns   any   more.     As   a   consequence   of   which   coastal   defense  strategies   and   structures   need   to   be   planned   and   designed   with   much   larger  flexibility  and  internal  redundancy.    Calling  for  a  different  approach  all  together.    The  current,  traditional  strategy  with  regard  to  coastal  defense  and  maintenance,  is  mainly  pretty  much  based  on  a  2-­‐Dimensional  approach.    A  way  of   coastline  defense  and  maintenance  which  is  loosing  terrain  faster  and  faster,  in  more  than  one  way.  Due  to  the  increase  in  the  unpredictability  and  impact  forces,  mitigating  measures   such   as   sand   nourishments   are   becoming   less   and   less   attractive   or  have   even   become   obsolete   all   together.     Also   due   to   their   often   marginal  structured   effectiveness   and   non   sustainability.     Whatever   sand   an   d   other  sediment  resources  shall  be  used  in  a  much  more  sophisticated  way.      Given  the  challenges  of   today,   the  way   forward   is  moving  on  towards  a   true  3-­‐Deimensional   approach,   covering   and   including   a   much   wider   area   of   the  foreshore  and  by  taking  into  account  all  of  the  relevant  coastal  features,  present  or   to  be  reconstructed  or  enhanced.     Integrating  them  into  adequate  and  much  more  extreme  weather  impact  safe,  resilient  and  sustainable  solutions.      One   of   the   challenges   to  meet,   is   that   the   required   knowledge   to   do   so,   often  seem   to  have  eroded  with  about   the   same  pace  as  many  of   these   re-­‐nourished  beaches,   dunes   and   foreshores.   The   industry   has   put   basically   all   its   effort   in  developing  bigger  and  faster  models,  however  without  extending  and  improving  their  functionalities  or  interaction.      When  evaluating  the  capabilities  and  computational  models  which  are  currently  on   the  market   for  design   and   impact   assessments   for   open   coastal  waters   and  sediment   dominated   coasts,   the   conclusion   cannot   be   other   than   that   over   the  past   decade   or   so,   in   particular   the   breakerzone   area   has   got   most   of   the  attention.  Apparently  hardly  any  attention  has  been  given   to   the  zone  between  the   most   landward   minus   3   meter   and   most   seaward   minus   15   or   20   meter  depth   contour.   And   so   gone   into   the   knowledge-­‐   and   tool   development   with  regard   to   (enhanced)   utilization   of   related   coastal   processes,   their   action   and  interaction  and    the  extreme  conditions  we  are  talking  about  right  now.    Based   on   this   assessment,   it   seems   fair   to   conclude   that   the   effort   now   really  needs   to   pick   up   and   catch   up   with   what’s   going   on   out   there.   Putting   the  processes,   natural   features   and   empirical   relationships   first.   With   some  additional   and   supportive   computational   model   development,   including  knowledge  bases  and  expert  systems.      

©  Marco  Pluijm    08/03/2017    

Which  development  shouldn’t  require  the  explosive  impact  of  a  weather  bomb  as  wake-­‐up  call.      The  Resilient  by  Nature  approach  is  an  instrument  which  has  helped  to  pave  the  way   for   such   an   holistic   based   development.   Based   on   “know   your   system”,  making  optimal  use  of  natural   features  and  their  characteristics  and  developed  from   there   onwards.   Providing   the   framework,   analyses   and   toolkit   to   build  upon.  Robust  and  moving  on  indeed.    More  information  about  the  Resilient  by  Nature  approach  for  coastal  challenges  can  be  found  on      https://www.slideshare.net/MarcoPluijm/resilient-­‐by-­‐nature-­‐update-­‐27012017