Tag Archives: Florida

Irma: From What Could Happen to What Did Happen…

17:00 UTC Tuesday, September 12

Emily Paterson, director – Model Product Management, RMS

Irma has now dissipated to the relief of many, not least those who experienced the storm’s wrath. The actuality of Irma was not nearly as bad as feared, as discussed in my colleague Tom Sabbatelli’s blog yesterday. Irma’s final path spared the major population centers of Miami and Tampa from the storm’s most damaging winds and storm surge.

Prior to and immediately after landfall, before we could see the final path and the actual impact of Irma, the best that anyone can do is look at the range of possible losses — as the final actual loss can only be known after an event is fully over and the details become clear.

To help our clients understand the potential magnitude of Irma’s insured loss during the storm’s approach, RMS provided guidance around what the distribution of potential wind losses looked like. But although we can have a good level of confidence in potential wind scenarios ahead of time, it is only part of the equation. As the hurricane approaches, we can provide guidance on the risk and identify areas that could be affected by storm surge and flooding, but the distribution of potential losses from these perils is uncertain as these losses are highly sensitive to the nuances of the storm’s final track and wind field structure.

Remember that the Saffir-Simpson scale no longer advises on the expected levels of storm surge following Hurricanes Katrina and Ike — storms that disproved the conventional understanding of the links between a hurricane’s intensity and its storm surge potential.

Now that Irma has gone, observations and imagery have started to come in that reveal the storm’s true impact. We are now able to shift our focus from “what could happen” to “what did happen”, from postulating potential wind loss distributions to delving into the hazard — including storm surge and flood — and damage observations to inform our final reconstructions of the event. Ultimately our understanding of the totality of losses from Irma will account for all loss drivers, including those which were too uncertain to estimate ahead of time. Storm surge, flood and other complicating factors, such as the evacuations, business interruption, and the prolonged and extensive power outages, among others, will all play a part in the final outcome.

While Irma has only dissipated very recently, what is already very clear is that Irma is a very complicated and complex event. How the interplay between wind, storm surge and flood plays out in terms of losses, and adding on top the impact of the complicating factors listed above, will ultimately dictate what the final losses will be.

Wind and surge observations from anemometers and gauges go a long way in helping us to better understand the hazard experienced on the ground, and are crucial as we look to reconstruct the hazard from Irma – our first step to understanding the full loss.

Satellite and drone imagery helps us go one step further and gives us a “birds eye view” of the damage experienced, helping to provide a fuller picture of both the type and level of damage, as well as a good indication of the extent. As we inspect the imagery we are looking for things that will help us refine our understanding of losses from this event — how far inland can we see surge damage? Is there roof damage from winds over a large area? We can use these observations to help refine and validate our understanding of loss. Another advantage of leveraging imagery is that it helps inform where we should focus our field reconnaissance efforts.

Figure 1. Map showing Key West Naval Base with photo image of residential area in the top right corner.  Source: OpenStreetMap

Figure 2: Residential area near Key West Naval Base, pre-event image from Google Earth, post-event aerial image acquired by NOAA on September 11, 2017

Our “boots on the ground” field reconnaissance approach really helps us refine our understanding with more detailed information. Not only does it help validate hazard observations with damage observations, but conversations with home and business owners, as well as those working on the recovery efforts, gives us insight into the prolonged effects impacting the affected communities, such as lengthy closures of businesses and insight into the types of internal and contents damage experienced by homeowners.  Our field reconnaissance plans are already underway and as those field observations come in, they will be fed into our process as well. The more information we have about the damage on the ground, the better our understanding of the full totality of losses from an event will be.

The Meteorology of Irma

20:00 UTC  Monday, September 11

Michael Kozar, senior modeler – Model Development, RMS

Steering the Storm

The synoptic patterns that steered Hurricane Irma this past week were complex. Like many intense storms that originate from an African easterly wave, Irma was steered westward across the tropical North Atlantic by the subtropical high to its north. As the storm moved into the Caribbean, a deep mid-latitude trough was sliding eastward across the East Coast of United States. The trough lifted poleward as Irma approached and a ridge steered Irma further to the west through the Turks and Caicos and the southern Bahamas, rather than allowing the storm to turn to the northwest towards the Mid-Atlantic United States.

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Irma in Miami: A Personal Perspective

19:00 UTC  Sunday, September 10

Victor Roldan, regional director – Caribbean and Latin America, RMS

I live in Brickell, in the Financial District of Miami, in a condominium block of some 30 stories on Brickell Bay Drive and SE 12th Street, very close to downtown Miami. The block faces the waterfront, four blocks from the Four Seasons, with the Mandarin Oriental just over the water on Brickell Key. This is an area that the insurance industry knows well, with many RMS clients operating their Latin American and Caribbean business from offices in and around a square mile from here.

I have lived in Miami for the past 15 years, and it is a great city. Similar to most Miami residents, I have experienced hurricanes, I know the difference between a hurricane and a major storm, and in my view here from my block some ten floors up, and despite of being 130 miles away from the eye, this is the worst I have ever seen. My family is safe, they are out of the state.

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Set to Impact Entire West Coast of Florida, Irma Raises Significant Storm Surge Concerns

14:30 UTC  Sunday, September 10

Tom Sabbatelli, hurricane risk expert – RMS

As Hurricane Irma makes landfall in the Florida Keys as a Category 4 storm, the range of the storm’s possible future tracks in the latest RMS HWind forecast product is rapidly narrowing. It is now certain that Irma will track along Florida’s west coast and impact all major population centers from Naples to Tallahassee.

What is less certain is the length of time Irma’s center will remain over water, with some scenarios projecting a landfall near Fort Myers and others delaying the landfall until Irma reaches the state’s Big Bend region.

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Irma: Westward Forecast Shift Creates Déjà Vu With Matthew

15:00 UTC  Saturday, September 9

Tom Sabbatelli, hurricane risk expert – RMS

The westward-moving trend of recent Hurricane Irma forecasts continues, with the Florida Keys, southwest Florida, and Tampa potentially within Irma’s sights. Although the National Hurricane Center forecast “cone of uncertainty” still covers much of south Florida, 83 percent of the individual forecasts analyzed by the RMS HWind forecast product bring the hurricane within 50 nautical miles of Key West, indicating that the Miami metropolitan region may be spared the worst of Irma’s winds. 75 percent of these forecasts also indicate a passage within 50 nautical miles of Tampa (see “Selected Probabilities” in the figure below).

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Hurricane Irma: Latest HWind Track Probability Analysis

07:00 UTC  Saturday, September 9

Michael Kozar, senior modeler – Model Development, RMS

The latest track probability analysis of the current model forecasts has been released by the RMS HWind team, based on forecast models initialized at 12:00 UTC Friday, September 8. This new proprietary track forecast probability product from RMS HWind provides unique insight into the likelihood of where a storm might go, to help deliver insights beyond what is available from public sources.

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Preliminary RMS Analysis of Potential Losses from Hurricane Irma

17:00 UTC  Friday, September 8 

Tom Sabbatelli, hurricane risk expert, RMS

For the last 48 hours, all the forecasts have been consistent in indicating that Hurricane Irma will have a significant impact in Florida, most likely making landfall in the state. The latest RMS HWind forecast shows it tracking more westerly than before, and this reduces the potential for loss because of the relative concentrations of exposure in the southern end of the Florida peninsula.

Based on today’s long-range forecast, RMS calculates there is still a 10 percent chance of wind losses from Irma exceeding US$85 billion. This assumes a U.S. landfall, with the scenarios in RMS modeling showing almost all of that insurance loss to be in Florida.

But the loss range in this preliminary analysis could easily move higher or lower depending on shifts in the storm track and its intensity. Irma’s anticipated direction of travel has been changing continually through the week, oscillating between both coasts of Florida. It is likely that this changeability will continue, and so the modeling uncertainties remain significant.

RMS will continue to update its analysis of potential insurance losses as Hurricane Irma moves closer to the U.S. coast.

Gearing Up for Irma: Using RMS Modeling to Generate Potential Loss Estimates

23:30 UTC  Wednesday, September 6

Tom Sabbatelli, hurricane risk expert, RMS

Hot on the heels of Hurricane Harvey, Irma looks like it could be the second major landfall in the U.S. this season, as it currently moves towards the Caribbean as a category 5 hurricane, with sustained winds around 185 miles per hour (297 kilometers per hour).

As always, the RMS Event Response starts early in the life of tropical storms, to provide the latest commentary, following up with RMS HWind footprints as data becomes available and providing initial sets of stochastic event selections around 48 hours before landfall. RMS Event Response practices have been designed to best serve our clients and the industry as a whole, and speculation of industry losses whilst such uncertainty remains can be counterproductive. Clients can see full information on the RMS Event Response processes by reading the following document available on RMS Owl.

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Irma: Using Cat in a Box Tools to Assess Scenarios

22:30 UTC  Wednesday, September 6

Sam Gibson, director – Consulting, RMS

With Irma moving swiftly through the Caribbean as a Category 5 hurricane, currently producing sustained winds around 185 miles per hour (297 kilometres per hour), concern is building as to the potential impacts of another major hurricane landfalling in the U.S. Although Irma’s actual path as it approaches Florida is very uncertain, there are analytical techniques available to help gain insight into the range of potential damage.

The RMS Cat in a Box (CIAB) application is designed for the assessment of parametric contracts, and can evaluate the probability of storms intersecting a specific geographic region whilst having certain severity characteristics. The application will output the list of events which intersect these areas and produce the associated Exceedance Probability (EP) curve.

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Just Tell Me Whether Andrew is Coming

On Saturday, August 22, 1992, I met with Herb Saffir (coauthor of the Saffir-Simpson Scale) in his Coral Gables office, south of downtown Miami, discussing a manual for post-storm damage investigation. I was also due to be the hurricane scientist member of a panel that Herb was chairing for the American Society of Civil Engineers. As the meeting ended it became apparent that Andrew, which had become a hurricane that morning, was approaching the Bahamas and was not going to recurve northward as hoped. It was coming right at us.

My home was in Coconut Grove, about three miles south of downtown Miami. I called my wife and told her to get to the Publix supermarket since a hurricane warning was imminent and we knew from earlier storms that there would soon be a run on supplies. I headed off to Home Depot for plywood and wondered how I could protect the house and still make my scheduled research reconnaissance flight into the storm on Sunday, working on one of the National Oceanic and Atmospheric Administration’s (NOAA) P3 Hurricane Hunter aircraft. As a hurricane wind specialist, I would be monitoring the wind field and radar displays over a proposed ten-hour mission. That mission was scrubbed when it became apparent that the aircraft would need to be evacuated from their base at Miami International Airport.

Instead, the Air Force Reserves of the 53rd Weather Squadron out of Keesler Air Force Base in Biloxi, Mississippi, flew a C-130 into the storm late Sunday, while I thankfully completed my shutters and we accommodated some friends (and their pets) who lived in a storm surge evacuation zone. Our home was near 20 feet (6 meters) above sea level on the coastal ridge in Coconut Grove, so flooding would not be a problem.

Well, Andrew hit overnight, and by 9 a.m. Monday morning, we seemed to be OK. Lots of trees were down and the power out but the house was intact with just a few broken roof tiles and one cracked window. We walked down to Biscayne Bay to check on the flooding and took some pictures, feeling the excitement of viewing a dramatically changed landscape. The mood changed when we received a call (yes, the phones were working even though there was no power) from another friend who was crying and upset about damage further south. We spent hours picking our way about 10 miles south to find that our guest’s home in “Whispering Pines” was within ground zero of the northern eyewall of Andrew. Their roof covering was peeled, double front doors were blown in, and all their living room furniture had been blasted through a sliding glass door into their pool.

Our friends were in shock and time was short due to an impending curfew so we made our way to the main north-south drag, U.S. Route 1 or Dixie Highway (difficult since all the street signs were blown down) for the drive back to Coconut Grove. We were marveling at the lack of any organized response, when we noticed a white school bus making its way southward on US 1.  We couldn’t hold back tears when we saw that the first responders were the City of Charleston Police Department. This was pay back from 1989, when Charleston was hit by Hurricane Hugo and Miami Metro-Dade County helped in the response.

Kate Hale, Emergency Director, Miami-Dade County – interviewed by local TV with regards to response to Hurricane Andrew

Overnight more than 200,000 were left homeless without power and with few supplies. Fifteen died from blunt trauma or drowning in the storm surge. It took days for significant relief to arrive with Kate Hale, the Miami-Dade County emergency director pleading “Where the hell is the cavalry on this one?” Despite the slow pace of response, it was amazing how the communities of South Florida pulled together to help each other out, with neighbors helping each other and sharing supplies.

It was also amazing that the Air Force crew on that C130 flew all night, monitoring Andrew as it strengthened through landfall and continuing to fly a hazardous pattern over land as the storm progressed inland. For several months’ afterwards, my team at NOAA’s Hurricane Research Division worked to piece together data and reconstruct Andrew’s wind field.  We visited sites with incredible damage where lives were lost. The public sent data in and we worked with wind engineering colleagues (Tim Reinhold from Clemson) who borrowed the Virginia Tech wind tunnel to test anemometers similar to the one that measured the peak wind speed in Perrine.

Miami Herald July 22, 1993

State Attorney General Janet Reno called to check on how strong the winds really were to allay some of the rumors swirling around. The Miami Herald published our wind footprint on the front page in 1993, indicating that the highest winds were north of where originally thought.  Our work was finally published as a two-part paper in Weather and Forecasting, which set the stage for objective analysis of hurricane wind fields. Back then the reconnaissance aircraft did not have a way to measure the winds near the surface, so storm intensity was estimated as a fraction of the maximum flight-level winds, resulting in a Category 4 assessment on the Saffir-Simpson scale. After 10 years, analysis of measurements closer to the surface from a new type of instrument, the GPS dropwindsonde, suggested that Andrew may have been a Category 5 storm at landfall. In 2009, research from an even newer instrument (Stepped-Frequency Microwave Radiometer), that remotely senses wind speed from the radiative emission of sea foam, reinforced the Category 5 assessment.

Hurricane Andrew had a profound effect on everyone living in South Florida at the time. It is one of those life milestones from which we measure everything before or after. Miami-Dade County responded with a tough new building code with product testing and enforcement, which influenced the eventual development of a unified Florida Building Code.  And it kickstarted the insurance industry into using sophisticated models that could estimate the risk of future Andrews, and performance in emergency management and response was found to influence presidential elections. The rebuilding created an economic boom, but many folks moved away while others moved in transforming rural areas such as Homestead in Miami-Dade, from farm fields into suburbs.

And for me, I went on to develop a research analysis system called H*Wind, now fully within RMS, which now allows us to monitor and analyze the wind field in real time using every piece of data we can get our hands on, such as satellite, dropsondes or portable MET towers placed just ahead of the storm by engineering and atmospheric science students and faculty at the University of Florida and Texas Tech. The HWind fields have become the analysis of record for significant landfall events and a standard for model evaluation with hundreds of citations in peer-reviewed scientific publications.

We work with scientists from all over the world to help develop cutting edge techniques for remote sensing of winds from space, or to provide the best possible forcing for a storm surge or wave model. We have a much better idea of the intensity and extent of the damaging winds now, and also developed new damage scales based on integrated kinetic energy that consider the destructive potential of large storms. Our extensive enhanced archive of historical storms is now helping us to design and evaluate new hurricane forecast products that are destined to find their way into RMS(one). RMS HWind is now the world’s leading provider of tropical cyclone wind field data, with observation-based data products for both real-time and historical wind field analyses in the western North Atlantic, Eastern Pacific and Central Pacific basins.

Andrew occurred during a year forecast to have “below normal” activity.  I’m often asked, “What kind of year are we going to have”? My answer? It doesn’t matter… just tell me whether Andrew is coming.