South Florida Storm Surge

Transcription

1 South Florida Storm Surge Highest storm tide Everglades City/Chokoloskee in area closest to landfall Nevertheless, storm tide as high as 6 feet along Biscayne Bay about 90 miles from eye of Irma! Closer approach of Irma to SE Florida would have increased storm tide levels further MIAMI SOUTH FLORIDA

2 Smallwood Store: Chokoloskee, FL Location of highest inundation in mainland South Florida: estimated 9.5 ft above water level and 8 ft above ground Water mark on pilings under building. No flooding noted inside building (which was closed and door locked but survey team was able to peek in through window) Challenge in converting inundation to values above datums such as NAVD88 and MHHW Determined reasonable value above MHHW by calculating approximate tide level/height from nearby Everglades City tide tables Water level about 1 ft below high tide at time of survey. Estimated 8.2 ft MHHW which matches up well with inundation above ground

3 Tin City: Naples Bay/Naples, FL Area of greatest concern for rapidly rising surge on back side of Irma eye wall Water rose 8 feet in just over 9 hours (min. 3.9 ft below MHHW at 1200 EDT to max ft MHHW at 2124 EDT). Max rate of rise: 3 ft/hr. Gauge location on bridge about 1/8 mile north of dock in picture at left Dock breaking away possibly due to force of rapidly rising water Inundation inside restaurant next to dock Data from USGS Rapid Deployment Gauge at Naples Bay

4 Irma Storm Surge Miami/Coconut Grove Courtesy WPLG Miami 4-6 ft inundation within 2 blocks of bay, despite eye of hurricane 90 miles away!

5 Irma Storm Surge Matheson Hammock Park (South of Miami) About 3-5 above ground level in restaurant/restroom/parking lot

6 Irma Storm Surge Brickell/Downtown Miami Courtesy Philippe Houdard 3 ft inundation (above ground)

7 Poll Time What is the best case scenario regarding surge for a tropical cyclone moving northward in the vicinity of Florida? A. To the west of the state. B. To the east of the state. C. Up the spine of the state.

8 Evolution of Potential Surge Threat Graphics with Shifting Track Forecast

9 Evolution of Potential Surge Threat Graphics with Shifting Track Forecast

10 Hurricane Irma Shifting Forecast Forecast Surge Potential adjusted from 4-6 feet 9/8 at 5AM to 7-10 feet across southern Lee County 9/8 at 11PM

11 10% vs 20% Exceedance Examples Hurricane Irma Advisory 39 5

12 Observed Irma Track and Simulated Surge Sanibel Naples Marco Everglades City

13 Observed vs Forecast Simulated Surge Sanibel Sanibel Naples Marco Everglades City Naples Marco ~ 30 nm Everglades City ~ 50,000 people with 3+ foot surge inundation ~ 200,000 people with 3+ foot surge inundation Observed Track Forecast Track from 5 PM Saturday, September 9 th Advisory

14 2017 Hurricane Irma Statistics Second landfall as CAT 3 (115 mph) near Marco Island at 3:30 pm Storm tide of 6-10 ft AGL in the unpopulated coast south of Marco Island. Tides of 3-5 ft AGL from Marco Island to Fort Myers. 92 U.S. Fatalities, 83 were Florida Residents

15 Hurricane Irma The Big Blowout Tides 4-7 feet below normal in Tampa Bay Talking about negative storm surge potential as early as 9/6, but were you expecting this?

16 Hurricane Irma Storm Surge Feet Above MHHW Feet Above MHHW