Hurricane Threat and Risk Analysis in Rhode Island presented at the July 24, 2014 Beach Special Area Management Plan Stakeholder meeting. Dr. Isaac Ginis, URI Graduate School of Oceanography View the video here: http://new.livestream.com/universityofrhodeisland/StormRecoveryRI

1. Graduate School of Oceanography
Isaac Ginis, Richard Yablonsky,
and Tracy McCormick
The Hurricane Threat and Risk
Analysis in Rhode Island
Hurricane Gloria on Sept. 27, 1985 (NOAA)
Beach SAMP Stakeholder Meeting:
Hurricanes and Storm Recovery in Rhode Island
July 24, 2014

2. • Frequency and severity
– How often do hurricanes make landfall?
– Where?
– How strong?
• Physical hazards
– What is the spatial pattern of the wind?
– How high is the storm surge?
– How much rain falls?
• Vulnerability
How much damage is caused by physical hazards?
RI Hurricane Threat

3. Tropical Cyclones Impacting RI since 1851
Total Number: 56

4. Tropical Cyclones Impacting RI since 1851

5. Great Colonial Hurricane of 1635
Figure 2.1 Track of the Great Colonial hurricane of 26 August 1635, with hourly positions in local standard time
and central pressure in millibars. Possible 80°F SST isotherm also shown.
Jarvinen (2006)
Storm Tides
Figure 2.2 Track of the Great Colonial hurricane of 26 August 1635, with hourly positions in local standard time,
pressure in millibars and SLOSH model maximum over water 1-minute wind speed in miles per hour. Circles
represent location of maximum wind with radius given in statute miles. Wind vectors show where maximum wind
is occurring at that time. Wind barbs in mph.

6. Great September Gale of 1815
Figure 3.1 Track of the Great September Gale on September 23, 1815, with hourly positions in local standard time
and central pressure in millibars.
Figure 3.2 Track of the September 23, 1815 hurricane with hourly positions in local standard time, pressure in
millibars and SLOSH model maximum over water 1-minute wind speed in miles per hour. Circles represent
location of maximum wind with radius given in statute miles. Wind vectors show where maximum wind is
occurring at that time. Wind barbs in mph.
Figure 3.3 Graphical computation of the storm tide hydrograph from the addition of the SLOSH and tide
hydrographs at two locations. The peak of the storm tide hydrograph is compared to the observed height. SLOSH
model over water 1-minute wind speeds in miles per hour are plotted with wind barbs indicating direction.
Jarvinen (2006)
Storm Tides

7. Storm Surge: New England Hurricane (1938)

8. Hurricane Sandy, 2012 1938 Hurricane
Sept 20
Sept 21
Oct 26
Oct 29
A tale of Two Hurricanes

9. • 8:30 am – hurricane centered near Cape Hatteras
• 2:30 pm – made landfall in Long Island
• 4:00 pm – made landfall in CT, RI
• 6:00 pm – reached Vermont
• 10:00 pm – crossed into Quebec
September 21, 1938
Forward speed reached 70 mph, the highest recorded!

10. Sandy: Maximum Sustained Winds (kt)

11. Sandy: Maximum Wind Gusts (kt)

12. Hurricane Wind Measurements –
WeatherFlow Mesonet
GSO Anemometer: Monday, Oct 29, 2012
100 anemometers designed to survive hurricane winds
Invaluable source of high quality hurricane wind measurements

13. Inland Flooding: Connie & Diane (1955)
CT
State
Library,
State
Archives,
File
Name
55flood17
NOAA/WPC
NOAA/WPC
Naugatuck, CT: August 19, 1955

14. Inland Flooding: Esther (1961)
NOAA/WPC

15. Inland Flooding: Irene (2011)
NOAA/WPC
Margaretville, NY
VT Route 100
Windham, NY
Windham, NY Wilbur’s Pt., Fairhaven, MA

16. • Most hurricanes approaching RI undergo a
transition from pure Tropical to “Extratropical”.
This transition implies significant changes in the
storm size, wind structure and rainfall pattern.
• The area of high winds and rain often expands
significantly. As a result, a wider area is affected
and storm’s total energy increases in many
cases.
Common Characteristics of RI Hurricanes

17. Cyclones: Tropical vs. Extratropical (Nor’easters)
Hurricane Katrina: August 28, 2005 “Superstorm”: March 13, 1993
• Derives energy from ocean surface
via release of latent heat in
convective clouds
• Derives energy from horizontal
temperature gradients (baroclinic
instability)
• Develops best in a barotropic
environment, far from jet stream
disturbances
• Develops best in a highly
baroclinic environment, close to
jet stream disturbances

18. “Late” extratropical transition
of Hurricane Arthur (July 1-7, 2014)
Escuminac, N.B.
Eastern Canada
Fredericton, N.B.

19. Frequency: Some computer models indicate either
reduction or increase in TC frequency. However, most
models show reduction of 0-20%. We have very low
confidence in projected changes in individual basins.
Tropical Cyclone Projections
Due to Global Warming
Intensity: More intense tropical cyclones (2-11% for an
IPCC A1B scenario). The frequency of the most intense
(rare/high-impact) storms will likely increase by a
substantially larger percentage in some basins.
Rainfall: Rates are likely to increase. The projected
magnitude is on the order of +20%.

20. “Downscaling” Method to Model the Impact of
Global Warming on Frequencies and Intensities
of Atlantic hurricanes
Source: Bender et al., Science, 2010.

21. 21st Century Climate Warming Projected
Changes in Atlantic Hurricane Frequency
Colored bars show changes for the 18 model CMIP3 ensemble (27 seasons); dots
show range of changes across 4 individual CMIP models (13 seasons).
Cat 4+5 frequency:
81% increase, or
10% per decade
Source: Bender et al., Science, 2010.
Estimated net impact
of these changes on
damage potential:
+28%

22. Hurricane Risk Analysis in RI
• How well do we understand the hurricane risk?
• Do we have necessary modeling tools?
…Not really…
• The primary tool is FEMA’s HAZUS based on
NOAA’s SLOSH model developed in the mid
1960s

23. Parametric Wind Model Used in SLOSH
Radial distance
WindSpeed
Simplified Axisymmetric Wind Profile
Typical parameters used: Vm, Rm, Pc, Po
Asymmetries
are added by
including
translation
velocity
vector.
Not suitable for RI
hurricanes
undergoing extra-
tropical transition!

24. A Need for Actionable Science
for Risk-informed Decisions
• RI needs robust, scientifically defensible
modeling tools to quantify the combined
coastal and inland hazards from hurricanes.
• Advanced modeling tools will help to more
accurately and clearly communicate
hurricane risks to RI stakeholders, including
threats to life, property and existing or
planned infrastructure.

25. Hurricane Risk Modeling Strategy for RI
To use advanced
hurricane-ocean coupled models at
open-ocean scales (a),
multiple coastal ocean circulation,
surge, and wave models from
the shelf (b) to estuaries (c), to
urbanized estuary-tributary interface (d),
combined with watershed rainfall runoff
and river flood models and environmental
biogeochemical/ecological models

26. Numerical Weather Prediction
Hurricane Models
•The 3-D physical
processes governing the
evolution of the
hurricane are simulated,
resulting in realistic
estimates of the surface
wind and rainfall.
•This approach must be
adopted for hurricane
risk analysis in RI

27. U.S. Operational Hurricane Models
• GFDL/GFDN – used by National Hurricane Center (NHC)
in the Atlantic Ocean and East Pacific since 1995 and
Joint Typhoon Warning Center (JTWC) in all ocean basins
since 1998
• HWRF – used by NHC in the Atlantic since and East
Pacific in 2007 and JTWC in the West Pacific since 2013
The GSO hurricane research group has been involved in the
development and improvements of GFDL/GFDN and HWRF
models in collaborations with NOAA and Navy scientists.

28. Nested Movable Grid Configuration
in Hurricane Models

29. GFDL Hurricane-Ocean Coupled Model
Forecast of Hurricane Katrina (2005)

30. Applying NOAA’s GFDL model for wind field
simulation during hurricane landfall
Hurricane
Isabel (2003)

31. Numerical weather prediction vs.
parametric wind fields

32. Landcover Variability in RI and Hurricane Wind
•Different landcovers (or
surface roughness) have
different “frictional”
characteristics which
dramatically affect the winds
near the ground.
• Variations in landcover are
responsible for most of the
local variability in the wind
fields over relatively small
distances.
(Landcover refers to the homes, forests, fields, and rivers)

33. Hypothetical “Hurricane Rhody”
High-impact, physically realistic scenario based
on historical hurricanes that affected RI

34. Summary
• Robust hurricane risk analysis is required for
better preparation and mitigation of hurricane
hazards in RI.
• Advanced wind, coastal and inland flood models
will improve accuracy of storm-induced and
post-storm environmental impacts.
• Climate change-induced increases in hurricane
intensity, rainfall, and sea level rise will
exacerbate wind, inland and coastal flooding
impacts.