Superstorm 93: A Case Scenario 1215 March 1993

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Superstorm 93 A Case Scenario12-15 March 1993

• What can we learn about forecast and warning
  needs and uses from an extreme event?
• Project supported by
• NCAR/Dir, NSF/ATM, NCAR/ESIG
• Researchers
• M.H. Glantz, R. Morss, J. Tribbia,
• E. Grunfest, L. Naranjo
• e-mail glantz_at_ucar.edu
• 12 January 2004

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What do we expect for this study?

• To know the road ahead as those coming back
• It can contribute to the education and training
  of professionals and students about
  climate-environment-society interactions
• The case-scenario can be used as a climate change
  impacts analogue, e.g., forecasting by analogy
• The study provides an opportunity to investigate
  the notion of an early warning cascade
• The topic brings together weather, climate
  variability and climate change researchers, all
  of whom are interested in extreme meteorological
  events
• What does it mean to say the forecast was a
  success five days in advance of its impacts?
• Lessons were learned from Superstorm 93,
• Butwere those lessons applied?
• If not, why not?

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Weblines referring to Super events
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SuperstormWhat it was

• The "Superstorm" began to develop on March 12th
  off the Gulf of Mexico, near the Texas-Mexican
  border, as a cyclone of low level pressure
• created when a mass of 20 - 30 F air collided
  with 70 - 80 F air.
• It rapidly intensified, because of the winds
  aloft reaching to 140 knots, and the temperature
  difference.
• It moved rapidly into the northwestern Florida on
  March 13th.
• A strong squall line developed as it reached the
  Florida coast.
• This created storm surges up to 12 feet, and
  hurricane force winds.
• FROM www.atmos.albany.edu/das/classes/atm422

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Characteristics of Superstorm 93

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Substantial meteorological interest in Superstorm
93

• numerous research publications on the storm,
  e.g.,
• Trilogy of papers in BAMS, 1995
• Kocin et al.
• Uccellini et al.
• P. Caplan
• Bosart et al., 1996, Mon. Wea. Rev.
• Numerous conference pre-prints and other
  literature
• Course developed at University of Illinois,
  Urbana-Champagne Superstorm 93 A Case Study
  Curriculum

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Using Superstorm for the enhancement of usable
science

• Superstorm can be used
• to identify new (since 93) technologies and
  forecasting techniques that are being or could be
  used
• To produce better forecasts of a storms onset
• To produce better forecasts as a storm progresses
  
• To increase lead time from forecast to impact
• To develop scenarios by hindcasting could
  forecasts have been issued earlier? What is
  considered appropriate usable lead time from
  forecast to impact forecast users with a wide
  range of different needs?
• Lessons learned may serve as examples for other
  activities focusing on usable weather
  information, e.g., THORPEX, USWRP

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Using Superstorm for theenhancement of societal
value

• Would a lead time of more than a 5-days generate
  additional benefits?
• Were short-term forecasts communicated
  effectively?
• e.g., understood by users
• Review how various societal sectors responded
• To the forecasts
• To the impacts
• Can assess the value of longer lead probabilistic
  information
• Were the adverse impacts foreseeable?
• Can ascertain the extent of societal preparation
  for an increase in frequency or intensity of such
  events (as has been suggested by various global
  warming researchers)

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Superstorm What it did nationally

• Storm affected 26 states in all. Largest area
  affected by such a storm.
• Dumped over 20 inches of snow in many parts of
  the Southeast--Totally unheard of.
• Caused a storm surge of over 10 feet in parts of
  Florida as well as winds of Hurricane Force as
  far south as Havana, Cuba.
• Characteristics of a Hurricane or Tropical Storm.
  
• Most powerful winter storm to affect the
  Continental United States since the Blizzard of
  1888.
• More than 240 death attributed to the storm.
• Caused approximately 6 billion dollars in
  damage.

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Superstorm 93 Impacts

• Storm of the Century   
• Superstorm 1993 was the deepest ETC to occur over
  the Gulf of Mexico in the 40-year period
  19571996  
•  Battered the eastern US from March 12-15,1993
  with tornadoes, high winds, record low pressure
  and very heavy snows.
• 3-6 billion in damages and 270 deaths were
  attributed to the storm over land with 48 more
  missing at sea.
• Every airport on the east coast was closed at one
  time or another for the first time ever in a
  single storm.
• 2-3 inches per hour snowfall rates were common
  and the snow caused hundreds of roofs to
  collapse.
• Homes also fell into the sea or received damage
  by wind or waves on the west coast of Florida,
  along the outer banks of North Carolina, and on
  Long Island.
• Fallen tree limbs and power lines left 3 million
  people along the storms path in then dark.
• Fifteen tornadoes in Florida killed 44 while 6
  inches of snow fell on the Florida Panhandle.
• Mount LeConte in Tennessee received 56 inches of
  snow. 43 inches fell at Syracuse, NY, 27 in
  Albany, NY, 20 inches at Chattanooga, TN, 16 in
  Roanoke, VA.
• Winds over 100 were reported on the Dry Tortugas
  (west of Key West, FL), in North Carolina on
  Flattop Mountain
• Winds over hurricane force were reported from
  Louisiana and Florida to New York and New
  England.

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Superstorm-93s impact in Florida

• In Florida it was the No-name storm
• It was not in the hurricane season, e.g., it was
  an unnamed hurricane-like storm
• Florida's Gulf coast
• Hurricane force winds
• 12 ft storm surge
• 14 tornadoes
• 18,000 homes destroyed
• 500 million in property damage
• 26 lives lost

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Superstorm What it did locally
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Dixie County, Florida Report on the impacts of
Superstorm 93
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Superstorm what it did internationally

• Cuba (Naranjo, 2004 Alfonso and Naranjo, 1996)
• Hurricane force winds as far south as Havana,
  Cuba
• Black out in Havana, Cuba
• On the 12th of March, the low moved across the
  Gulf coast and caused destruction even down into
  Cuba where 3 were killed.
• Most damaging Squall Line registered in Cuba
  during the winter this was associated with the
  superstorm that hit the Eastern half of the
  United States.
• Canada
• 131 MPH occurred at Grand Etang, Nova Scotia
• We also have an associated study
• Supercyclone Orissa, India 1999 (P.I. Ashutosh
  Mohanty, Utkal University)

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Comments on forecasts related to superstorm 93

• The National Weather Service predicted a "storm
  of historic magnitude" 48 hours in advance.
• In contrast to many of the previous major storm
  events, the overall forecast for the March 1993
  superstorm was very successful (uccellini et al,
  1995)
• Cyclogenesis along the East Coast was predicted
  up to five days in advance (uccellini et al,
  1995)
• Although Superstorm 1993 was well forecasted
  several days in advance over the northeastern
  United States, the initial cyclogenesis over the
  northwestern Gulf of Mexico was poorly forecast
  (e.g., Dickinson et al. 1997)
• Differences in the model forecasts complicated
  the tasks of forecasting the exact location,
  intensity, and track of the cyclone, the
  rain-snow line, and snowfall amounts, especially
  in major cities along the East Coast. (uccellini
  et al, 1995)
• Forecasters had predicted high winds, but not
  high water, early in the storm. (St. Petersburg
  Times)

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Selected Comments, Continued

• Dickinson et al. (1997) established that the NCEP
  and to a lesser extent operational prediction
  models performed poorly in predicting the
  intensity of the initial cyclogenesis over the
  Gulf of Mexico.
• They showed that the initial poor model forecasts
  of Superstorm 1993 could probably be attributed
  to a combination of
• (1) a significant underestimation of the initial
  strength of the surface baroclinity over the
  northwest Gulf of Mexico that was apparent in the
  buoy/C-MAN observations reported by Gilhousen
  (1994),
• (2) a misrepresentation of the strength of the
  warm oceanic ring situated over the northwestern
  Gulf of Mexico (Gilhousen, 1994),
• (3) a failure of the NCEP models to represent
  properly the bulk effects of cumulus convection
  associated with the massive convective outbreak
  over the Gulf of Mexico during the incipient and
  rapidly intensifying phase of the storm, and
• (4) an underestimation of the intensity of a
  dynamical tropopause disturbance embedded in the
  subtropical jet stream that helped to trigger the
  massive convection and initial cyclogenesis over
  the Gulf of Mexico.
• It is quite likely that a better representation
  of the marine environment over the Gulf of Mexico
  at the time of the incipient cyclogenesis would
  have resulted in better model forecasts of the
  initial storm development.

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Utility of the case-scenario approach

• Perfect information about the forecasts
• Perfect information about the storms evolution
  and impacts
• Can generate scenarios based on reality
• Policy makers can relate to the study. Many were
  involved in the storm in some way.
• Use of findings as analogue to other extreme
  winter storms
• SWOC assessment (strengths, weaknesses,
  opportunities and constraints) of forecasts and
  responses
• The studys findings can be used in studies of
  societal responses to global warming

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Foreseeability

• Foreseeability
• to see beforehand, to foreknow
• application of the concept to determine
  responsibility for damage
• Foreseeable risk --- a risk whose consequences a
  person of ordinary prudence would expect might
  occur
• Foreseeability differs from predictability or
  forecasting because it neither depends on nor
  implies the quantitative description of the
  probability of harm
• Foreseeability encompasses not only that which
  the defendant foresaw, but that which the
  defendant ought to have foreseen (Gifis, 1991,
  p. 196)