Tag Archives: Hurricane

Is this the year that breaks the streak?

Sports fans around the world have witnessed impressive winning streaks throughout history. After capturing two consecutive UEFA European Championships (2008, 2012) and a World Cup championship (2010), the Spanish National Football Team entered the 2014 World Cup in Brazil as the top-ranked squad in international competition. The dominant Spaniards were among the international sportsbooks’ favorites to bring home the trophy once again.

Instead, surprising defeats at the hands of the Netherlands and Chile eliminated Spain at the group stage. Spain’s streak of dominance came to a sudden end, marking the earliest World Cup exit for a defending champion since 1950.

From a meteorological perspective, the United States is currently riding its own streak: ten Atlantic hurricane seasons without a major hurricane (category 3 or above) making landfall, the longest such stretch in recorded history. With another hurricane season upon us, many will be keeping a keen eye on the Atlantic this summer to see if this impressive streak will continue.

Global forecasting groups, such as Colorado State University and Tropical Storm Risk, have issued their tropical storm and hurricane activity forecasts for the 2016 Atlantic hurricane season. Christopher Allen of the RMS Event Response team has authored an excellent summary of their forecasts in the RMS 2016 North Atlantic Hurricane Season Outlook published this week on RMS.com.

You can also listen to my summary of the season’s forecasts during my talk to AM Best TV’s John Weber. In summary, most forecasts are predicting anywhere between near-average to above-average activity in the Atlantic basin, reflecting conflicting signals in the key indicators that influence hurricane formation.

Will we have increased hurricane activity?

One factor that may support increased hurricane activity this season is the anticipated state of the El Niño-Southern Oscillation, or ENSO. As reported on this blog several months ago, many ENSO forecasts project a transition out of last year’s historic El Niño phase into a La Niña phase, which is historically more favorable for hurricane development. Wind shear, detrimental to tropical cyclone formation, typically is reduced in the Atlantic basin during La Niña phases of ENSO.

Mid-May 2016 observations and model forecasts of ENSO, based on the NINO3.4 index, through March 2017. Positive values correspond with El Niño, while negative values correspond with La Niña. Source: International Research Institute for Climate and Society

Conversely, some forecasts predict a cooling of Atlantic sea surface temperatures (SSTs), which would oppose any support provided by a forecasted La Niña and reduce the potential for an active hurricane season. This cooling has been driven by a lengthened positive phase of the North Atlantic Oscillation (NAO), which causes stronger than normal trade winds in the tropical North Atlantic and upwelling of deeper cold ocean water near the surface.

February-April 2016 sea level pressure anomalies in the North Atlantic Ocean (hPa, anomalies with respect to 1981-2010 climatology). Anomalously high pressure evident in the Azores and the mid-latitude North Atlantic signals a positive phase of the NAO. Source: National Centers for Environmental Prediction Monthly Reanalysis (Kalnay, E. and Coauthors, 1996: The NCEP/NCAR Reanalysis 40-year Project. Bull. Amer. Meteor. Soc., 77, 437-471).

The Atlantic Multidecadal Oscillation may also be transitioning into a prolonged phase detrimental to tropical cyclone development, a theory often mentioned on this blog, although one that is still debated in the scientific community.

If considered in isolation, La Niña conditions and cooling Atlantic SSTs exert conflicting influences on Atlantic tropical cyclone development. However, forecasts contain key caveats that will ultimately determine this season’s activity:

  • Although a transition into a La Niña phase is widely anticipated, a late arrival would limit its ability to support development in the basin.
  • Further, forecasts of Atlantic sea surface temperature during August and September, the peak of hurricane season, remain conflicted.

Does the season’s early storm activity signify more activity?

Forecasts predicting above-average basin activity are understandable, given the early activity observed prior to the season’s official start. Tropical Storms Bonnie and Colin both formed before the second week in June, bringing heavy rainfall to South Carolina and the Gulf coast of Florida, respectively. Bonnie and Colin followed Hurricane Alex, the first January hurricane since 1938.

Bonnie’s formation marked the first time since 2012 that two named storms developed before June 1, the official start of hurricane season. The 2012 season ended with 19 total named storms, the third-most on record, including Superstorm Sandy, which caused more than $18 billion in insured losses.

Would the industry be prepared for the next major hurricane landfall? According to Fitch, the answer is yes: insurers and reinsurers in 18 coastal U.S. states would be equipped to handle one major event this season, although this resiliency has not been recently tested. More worrying, though, are the prospects of a large tail event or even multiple landfalling events, which may be supported by the right combination of oceanic and atmospheric influences.

With the hurricane season now officially underway, we will watch, wait and see how the season’s activity unfolds over the next few months. What is certain, though, is that streaks are made to be broken. It’s just a matter of when.

We’re Still All Wondering – Where Have All The Hurricanes Gone?

The last major hurricane to make landfall in the U.S. was Hurricane Wilma, which moved onshore at Cape Romano, Florida, as a Category 3 storm on October 24, 2005. Since then, a decade has passed without a single major U.S. hurricane landfall—eclipsing the old record of eight years (1860-1869) and sparking vigorous discussions amongst the scientific community on the state of the Atlantic Basin as a whole.

Research published in Geophysical Research Letters calls the past decade a “hurricane drought,” while RMS modelers point out that this most recent “quiet” period of hurricane activity exhibits different characteristics to past periods of low landfall frequency.

Unlike the last quiet period—between the late 1960s and early 1990s—the number of hurricanes forming during the last decade was above average, despite a below average landfall rate.

According to RMS Lead Modeler Jara Imbers, these two periods could be driven by different physical mechanisms, meaning the current period is not a drought in the strictest sense. Jara also contends that developing a solid understanding of the nature of the last ten years’ “drought” may require many more years of observations. This additional point of view from the scientific community highlights the ongoing uncertainty around governing Atlantic hurricane activity and tracks.

To provide our clients with a rolling five-year, forward-looking outlook of annual hurricane landfall frequency based on the current climate state, RMS issues the Medium-Term Rate (MTR), our reference view of hurricane landfall frequency. The MTR is a product of 13 individual forecast models, weighted according to the skill each demonstrates in predicting the historical time series of hurricane frequency.

Accounting for Cyclical Hurricane Behavior With Shift Models

Among the models contributing to the MTR forecast are “shift” models, which support the theory of cyclical hurricane frequency in the basin. This was recently highlighted by commentary published in the October 2015 edition of Nature Geosciences and in an associated blog post from the Capital Weather Gang, speculating whether or not the active period of Atlantic hurricane frequency, generally accepted as beginning in 1995, has drawn to a close. This work suggests that the Atlantic Multidecadal Oscillation (AMO), an index widely accepted as the driver of historically observed periods of higher and lower hurricane frequency, is entering a phase detrimental to Atlantic cyclogenesis.

Our latest model update for the RMS North Atlantic Hurricane Models advances the MTR methodology by considering that a shift in activity may have already occurred in the last few years, but was missed in the data. This possibility is driven by the uncertainty in identifying a recent shift point: the more time that passes after a shift and the more data that is added to the historical record, the more certain you become that it occurred.

The AMO has its principle expression in the North Atlantic sea surface temperatures (SST) on multidecadal scales. Generally, cool and warm phases last for up to 20-40 years at a time, with a difference of about 1°F between extremes. Sea level pressure and wind shear typically are reduced during positive phases of the AMO, the predominant phase experienced since the mid-1990s, supporting active periods of Atlantic tropical cyclone activity; conversely, pressure and shear typically increase during negative phases and suppress activity.

Monthly AMO index values, 1860-present. Positive (red) values correspond with active periods of Atlantic tropical cyclone activity, while negative (blue) values correspond with inactive periods. Source: NOAA ESRL

The various MTR “shift” models consider Atlantic multidecadal oscillations using two different approaches:

  • Firstly, North Atlantic Category 3-5 hurricane counts determine phases of high and low activity.
  • Secondly, the use of Atlantic Main Development Region (MDR) and Indo-Pacific SSTs (Figure 2) captures the impact of observed SST oscillations on hurricane activity.

As such, low Category 3-5 counts over many consecutive years and recent changes in the internal variability within the SST time series may point to a potential shift in the Atlantic Basin activity cycle.


The boundaries considered by RMS to define the Atlantic MDR (red box) and Indo-Pacific regions (white box) in medium-term rate modeling.

The “shift” models also consider the time since the last shift in activity. As the elapsed time since the last shift increases, the likelihood of a shift over the next few years also increases, which means it is more likely 20 years after a shift than two years after a shift.

Any uncertainty in tropical cyclone processes is considered through the “shift” models and the other RMS component models, based on competing theories related to historical and future states of hurricane frequency.

Given the interest of the market and the continuous influx of new science and seasonal data, RMS reviews its medium-term rates regularly to investigate whether this new information would contribute to a significant change in the forecast.

If we continue to observe below average tropical cyclone formation and landfall frequency, a shift in the multidecadal variability will become more evident, and the forecasts produced by the “shift” models will decrease. However, it is mandatory that the performance and contribution of these models relative to the other component models are considered before the final MTR forecast is determined.

This post was co-authored by Jeff Waters and Tom Sabbatelli. 

Tom Sabbatelli

Product Manager, Model Product Management, RMS
Tom is a Product Manager in the Model Product Management team, focusing on the North Atlantic Hurricane Model suite of products. He joined RMS in 2009 and spent several years in the Client Support Services organization, primarily providing specialist peril model support. Tom joined RMS upon completion of his B.S. and M.S. degrees in meteorology from The Pennsylvania State University, where he studied the statistical influence of climate state variables on tropical cyclone frequency. He is a member of the American Meteorological Society (AMS).

South Carolina Floods: The Science Behind the Event and What It Means for the Industry

South Carolina recently experienced one of the most widespread and intense multi-day rain events in the history of the Southeast, leaving the industry with plenty to ponder.

Parts of the state received upwards of 27 inches (686 mm) of rain in just a four day period, breaking many all-time records, particularly near Charleston and Columbia (Figure 1). According to the National Oceanic and Atmospheric Administration, rainfall totals surpassed those for a 1000-year return period event (15-20 inches (381-508 cm)) for parts of the region. As a reminder, a 1000-year return period means there is a 1 in 1000 chance (0.1%) of this type of event occurring in any year, as opposed to once every thousand years.


Figure 1: Preliminary radar-derived rainfall totals (inches), September 29-October 4. Source: National Weather Service Capital Hill Weather Gang.

The meteorology behind the event

As Hurricane Joaquin tracked north through the Atlantic, remaining well offshore, a separate non-tropical low pressure system positioned itself over the Southeast U.S. and essentially remained there for several days. A ridge of high pressure to the north acted to initiate strong onshore windflow and helped keep the low-pressure system in place. During this time, it drew in a continuous plume of tropical moisture from the tropical Atlantic Ocean, causing a conveyor belt of torrential rains and flooding throughout the state, from the coast to the southern Appalachians.

Given the fact that Joaquin was in the area, the system funneled moist outflow from it as well, enhancing the onshore moisture profile and compounding its effects. It also didn’t help that the region had experienced significant rainfall just a few days prior, creating near-saturated soil conditions, and thus, minimal absorption options for the impending rains.

It’s important to note that this rain event would have taken place regardless of Hurricane Joaquin. The storm simply amplified the amount of moisture being pushed onshore, as well as the corresponding impacts. For a more detailed breakdown of the event, please check out this Washington Post article.

Notable impacts and what it means for the industry

Given the scope and magnitude of the impacts thus far, it will likely be one of the most damaging U.S. natural catastrophes of 2015. Ultimately, this could be one of the most significant inland flooding events in recent U.S. history.

This event will undoubtedly trigger residential and commercial flood policies throughout the state. However, South Carolina has just 200,000 National Flood Insurance Program (NFIP) policies in place, most of which are concentrated along the coast, meaning that much of the residential losses are unlikely to be covered by insurance.


Figure 2: Aerial footage of damage from South Carolina floods. Source: NPR, SCETV.

Where do we go from here?

Similar to how Tropical Storm Bill reiterated the importance of capturing risk from tropical cyclone-induced rainfall, there is a lot to take away from the South Carolina floods.

First, this event underscores the need to capture interactions between non-tropical and tropical systems when determining the frequency, severity, and correlation of extreme precipitation events. This  combined with high resolution terrain data, high resolution rainfall runoff models, and sufficient model runtimes will optimize the accuracy and quality of both coastal and inland flood solutions.

Next, nearly 20 dams have been breached or failed thus far, stressing the importance of developing both defended and undefended views of inland flood risk. Understanding where and to what extent a flood-retention system, such as a dam or levee, might fail is just as imperative as knowing the likelihood of it remaining intact. It also highlights the need to monitor antecedent conditions in order to properly assess the full risk profile of a potential flood event.

The high economic-to-insured loss ratio that is likely to result from this event only serves to stress the need for more involvement by private (re)insurers in the flood insurance market. NFIP reform combined with the availability of more advanced flood analytics may help bridge that gap, but only time will tell.

Lastly, although individual events cannot be directly attributed to climate change, these floods will certainly fuel discussions about the role it has in shaping similar catastrophic occurrences. Did climate change amplify the effects of the flooding? If so, to what extent? Will tail flood events become more frequent and/or more intense in the future due to a rising sea levels, warming sea surface temperatures, and a more rapid hydrologic cycle? How will flood risk evolve with coastal population growth and the development of more water impermeable surfaces?

This event may leave the industry with more questions than answers, but one stands out above the rest: Are you asking the right questions to keep your head above water?

Coastal Flood: Rising Risk in New Orleans and Beyond

As we come up on the tenth anniversary of Hurricane Katrina, a lot of the focus is on New Orleans. But while New Orleans is far from being able to ignore its risk, it’s not the most vulnerable to coastal flood. RMS took a look at six coastal cities in the United States to evaluate how losses from storm surge are expected to change from the present day until 2100 and found that cities such as Miami, New York, and Tampa face greater risk of economic loss from storm surge.

To evaluate risk, we compared the likelihood of each city sustaining at least $15 billion in economic losses from storm surge – the amount of loss that would occur if the same area of Orleans Parish was flooded today as was flooded in 2005. What we found is that while New Orleans still faces significant risk, with a 1-in-440 chance of at least $15 billion in storm surge losses this year, the risk is 1-in-200 in New York, 1-in-125 in Miami, and 1-in-80 in Tampa.

Looking ahead to 2100, those chances increase dramatically. The chance of sustaining at least $15 billion in storm surge losses in 2100 rises to 1-in-315 in New Orleans, 1-in-45 in New York, and 1-in-30 in both Miami and Tampa.

Due to flood defences implemented since 2005, the risk in New Orleans is not as dramatic as you might think compared to other coastal cities evaluated. However, the Big Easy is faced with another problem in addition to rising sea levels – the city itself is sinking. In fact, it’s sinking faster than sea levels are rising, meaning flood heights are rising faster than any other city along the U.S. coast.

Our calculations regarding the risk in New Orleans were made on the assumption that flood defences are raised in step with water levels. If mitigation efforts aren’t made, the risk will be considerably higher.

And, there is considerable debate within the scientific community over changing hurricane frequency. As risk modelers, we take a measured, moderate approach, so we have not factored in potential changes in frequency into our calculations as there is not yet scientific consensus. However, some take the view that frequency is changing, which would also affect the expected future risk.

What’s clear is it’s important to understand changing risk as storm surge continues to contribute a larger part of hurricane losses.

From Arlene to Zeta: Remembering the Record-Breaking 2005 Atlantic Hurricane Season

Few in the insurance industry can forget the Atlantic hurricane season of 2005. For many, it is indelibly linked with Hurricane Katrina and the flooding of New Orleans. But looking beyond these tragic events, the 2005 season was remarkable on many levels, and the facts are just as compelling in 2015 as they were a decade ago.

In the months leading up to June 2005, the insurance industry was still evaluating the impact of a very active season in 2004. Eight named storms made landfall in the United States and the Caribbean (Mexico was spared), including four major hurricanes in Florida over a six-week period. RMS was engaged in a large 2004-season claims evaluation project as the beginning of the 2005 season approached.

An Early Start

The season got off to a relatively early start with the first named storm—Arlene—making landfall on June 8 as a strong tropical storm in the panhandle of Florida. Three weeks later, the second named storm—Bret—made landfall as a weak tropical storm in Mexico. Although higher than the long-term June average of less than one named storm, June 2005 raised no eyebrows.

July was different.

Climatologically speaking, July is usually one of the quietest months of the entire season, with the long-term average number of named storms at less than one. But in July 2005, there were no fewer than five named storms, three of which were hurricanes. Of these, two—Dennis and Emily—were major hurricanes, reaching categories 4 and 5 on the Saffir-Simpson Hurricane Scale. Dennis made landfall on the Florida panhandle, and Emily made landfall in Mexico. This was the busiest July on record for tropical cyclones.

The Season Continued to Rage

In previous years when there was a busy early season, we comforted ourselves by remembering that there was no correlation between early- and late-season activity. Surely, we thought, in August and September things would calm down. But, as it turned out, 10 more named storms occurred by the end of September—five in each month—including the intense Hurricane Rita and the massively destructive Hurricane Katrina.

In terms of the overall number of named storms, the season was approaching record levels of activity—and it was only the end of September! As the industry grappled with the enormity of Hurricane Katrina’s devastation, there were hopes that October would bring relief. However, it was not to be.

Seven more storms developed in October, including Hurricane Wilma, which had the lowest-ever pressure for an Atlantic hurricane (882 mb) and blew though the Yucatan Peninsular as a category 5 hurricane. Wilma then made a remarkable right turn and a second landfall (still as a major hurricane) in southwestern Florida, maintaining hurricane strength as it crossed the state and exited into the Atlantic near Miami and Fort Lauderdale.

We were now firmly in record territory, surpassing the previous most-active season in 1933. The unthinkable had been achieved: The season’s list of names had been exhausted. October’s last two storms were called Alpha and Beta!

Records Smashed

Four more storms were named in November and December, bringing the total for the year to 28 (see Figure 1). By the time the season was over, the Atlantic, Caribbean and Gulf of Mexico had been criss-crossed by storms (see Figure 2), and many long-standing hurricane-season records were shattered: the most named storms, the most hurricanes, the highest number of major hurricanes, and the highest number of category 5 hurricanes (see Table 1). It was also the first time in recorded history that more storms were recorded in the Atlantic than in the western North Pacific basin. In total, the 2005 Atlantic hurricane season caused more than $90 billion in insured losses (adjusted to 2015 dollars).

The 2005 Atlantic Hurricane Season: The Storm Before the Calm

The 2005 season was, in some ways, the storm before the current calm in the Atlantic, particularly as it has affected the U.S. No major hurricane has made landfall in the U.S. since 2005. That’s not to say that major hurricanes have not developed in the Atlantic or that damaging storms haven’t happened—just look at the destruction wreaked by Hurricane Ike in 2008 (over $13 billion in today’s dollars) and by Superstorm Sandy in 2012, which caused more than $20 billion in insured losses. We should not lower our guard.


Figure 1: Number of named storms by month during the 2005 Atlantic hurricane season

Table 1: Summary of the number of named storms in the Atlantic hurricane basin in 2005 and average season activity through 2014
* Accumulated Cyclone Energy (ACE): a measure of the total energy in a hurricane season based on number of storms, duration, and intensity


Figure 2: Tracks of named storms in the 2005 Atlantic hurricane season

2015 North Atlantic Hurricane Season: What’s in Store?

RMS recently released its 2015 North Atlantic Hurricane Season Outlook. So, what can we expect from this season, which is now underway?

2015 season could be the 10th consecutive year without a major landfalling hurricane over the United States.

The 2014 season marked the ninth consecutive year that no major hurricane (Category 3 or higher) made landfall over the United States. Although two named storms have already formed in the basin so far this year, Tropical Storm Ana and Tropical Storm Bill, 2015 looks to be no different. Forecast groups are predicting a below-average probability of a major hurricane making landfall over the U.S. and the Caribbean in the 2015 season.

The RMS 2015 North Atlantic Hurricane Season Outlook highlights 2015 seasonal forecasts and summarizes key meteorological drivers in the Atlantic Basin.

Forecasts for a below-average season can be attributed to a number of interlinked atmospheric and oceanic conditions, including El Niño and cooler sea surface temperatures.

So what factors are driving these predictions? A strong El Niño phase of the El Niño Southern Oscillation (ENSO) is a large factor, as Jeff Waters discussed previously.

Source: NOAA/ESRL Physical Sciences Division

Another key factor in the lower forecast numbers is that sea surface temperatures (SSTs) in the tropical Atlantic are quite a bit cooler than previous years. SSTs higher than 80°F (26.5°C) are required for hurricane development and for sustained hurricane activity, according to NOAA Hurricane Research Division.

Colorado State University (CSU)’s June 1st forecast is calling for 8 named storms, 3 hurricanes, and 1 major hurricane this season, with an Accumulated Cyclone Energy (ACE) index—used to express activity and destructive potential of the season—of 40. This is well below the 65- and 20-year averages, both over 100.

However, all it takes is one significant event to cause significant loss.

Landfalls are difficult to predict more than a few weeks in advance, as complex factors control the development and steering of storms. Despite the below-average number of storms expected in the 2015 season, it only takes one landfalling event to cause significant loss. Even if the activity and destructive energy of the entire season is lower than previous years, factors such as location and storm surge can increase losses.

For example, Hurricane Andrew made landfall as a Category 5 storm over Florida in 1992, a strong El Niño year. Steering currents and lower-than-expected wind shear directed Andrew towards the coastline of Florida, making it the fourth most intense landfalling U.S. hurricane recorded. Hurricane Andrew also holds the record for the fourth costliest U.S. Atlantic hurricane, with an economic loss of $27 billion USD (1992).

Sometimes, a storm doesn’t even need to be classified as a hurricane at landfall to cause damage and loss. Though Superstorm Sandy had Category 1 hurricane force winds when it made landfall in the U.S., it was no longer officially a hurricane, having transitioned to an extratropical storm.  However, the strong offshore hurricane force winds from Sandy generated a large storm surge, which accounted for 65 percent of the $20 billion insured losses.

While seasonal forecasts estimate activity in the Atlantic Basin and help us understand the potential conditions that drive tropical cyclone activity, a degree of uncertainty still surrounds the exact number and paths of storms that will form throughout the season. For this reason, RMS recommends treating seasonal hurricane activity forecasts with a level of caution and to always be prepared for a hurricane to occur.

For clients, RMS has released new resources to prepare for the 2015 hurricane season available on the Event Response area of RMS Owl.

New Storms, New Insights: Two Years After Hurricane Sandy

When people think about the power of hurricanes, they imagine strong winds and flying debris. Wind damage will always result from hurricanes, but Hurricane Sandy highlighted the growing threat of storm surge as sea levels rise.

While Sandy’s hurricane-force winds were not unusual, the storm delivered an unprecedented storm surge to parts of the Mid-Atlantic and Northeast U.S. In total, Sandy caused insured losses of nearly $20 billion in the U.S., 65 percent of which resulted from surge-driven coastal flooding.

Considering the hazard and severity of the event, we used Sandy as the first real opportunity to validate our hydrodynamic storm surge model, which we released in 2011 and embedded in the RMS U.S. Hurricane Model. We verified the model against more than 300 independent wind and flood observations, the Federal Emergency Management Agency’s (FEMA) 100-year flood zones, and the FEMA best surge inundation footprint for New York City. The model captured the extent and severity of Sandy’s coastal flooding exceptionally well.

We also conducted extensive analysis of claims data from Sandy, which involved reviewing nearly $3 billion in location-level claims and exposure data across seven lines of business, provided by several companies. The purpose of the study was to deepen our understanding of the impacts of flooding on coastal exposures, particularly for commercial and industrial structures.

What struck us was how vulnerable buildings are to below-ground flooding. In many cases, damage to ground- and basement-level property and contents contributed a much higher proportion of the overall losses than expected, particularly for commercial structures in New York’s central business districts.

This insight has prompted us to improve the flexibility of how losses are modeled for contents and business interruption, specifically for basements. Early next year, we will release an update to our flagship North Atlantic Hurricane Models to provide the most-up-to-date view of hurricane risk with new vulnerability modeling capabilities based on insights gained from Sandy.

The model update includes new location-specific content triggers to enable users to make business interruption loss projections dependent on either contents or building damage, rather than on building damage alone. The model also allows users to assess the impact of multiple basement levels in a building, as well as the total value of contents stored within.

The claims data analysis also highlighted the importance of using high-resolution data to model high-gradient perils, such as coastal flooding. Flood losses are extremely sensitive to the locations of coastal exposures, as well as the surrounding topographical and bathymetrical features. Using high quality data with location-level specificity across a variety of building characteristics, as well as a high-resolution storm surge model that can accurately capture the flow of water around complex coastlines and local terrain, minimizes uncertainty.

At this time, RMS remains the only catastrophe modeling firm to integrate a hydrodynamic, time-stepping storm surge model into its hurricane models to represent the complex interactions of wind and water throughout a hurricane’s life-cycle, and we continue to implement lessons learned from new storms.

2014 Atlantic Hurricane Season Update: Not Quite 2004

The 2014 Atlantic Hurricane Season is already half over, and with only five named storms in the books and El Niño conditions likely by late fall, all signs are pointing to a below-average season.

Over the last six weeks, organizations like Colorado State University (CSU) and the National Oceanic and Atmospheric Administration (NOAA) updated their seasonal outlooks with similar or slightly reduced numbers, attributing them to a variety of oceanic and atmospheric conditions acting to suppress activity, including cooler than normal sea surface temperatures, higher than normal sea level pressures, and stronger than normal wind shear.

Interestingly, the suppressed activity is not being attributed nearly as much to El Niño conditions as originally thought. Despite high likelihoods that the equatorial Pacific would warm to El Niño levels by late summer, observed El Niño Southern Oscillation (ENSO) conditions were neutral during the July and August period, according to the International Research Institute for Climate and Society.

Such observations have certainly impacted ENSO forecasts for the remainder of 2014 into 2015. As of September 4, the likelihood for El Niño conditions to form during the period from September to November dropped to 55% from a convincing 74% probability back in May. Despite this material reduction, most of the ENSO prediction models still forecast the onset of El Niño by early Fall, peaking during Northern Hemisphere winter 2014-2015 and lasting into the first few months of 2015.

Barring any late season surge in activity, this year will be a far cry from the busier seasons of the past, most notably the 2004 season. Like this year, 2004 was also impacted by weak, neutral El Niño conditions. However, the 2004 season was impacted by a rare type of storm known as Modoki El Niño in which unfavorable hurricane conditions are produced in the Pacific instead of the Atlantic Ocean, resulting in above average activity in the Atlantic.

The most notable U.S. hurricanes during the 2004 season were Hurricanes Charley, Frances, Ivan, and Jeanne. These four events damaged an estimated 2 million properties in Florida – approximately one in five houses – and caused more than $20 billion in insured losses throughout the U.S.

The strongest system to hit land that season was Hurricane Charley. The storm made landfall on the southwest coast of Florida on August 13 as a Category 4 hurricane, causing nearly $15 billion in economic damages – one of the most destructive hurricanes in U.S. history.

Just over three weeks later, Hurricane Frances, a large, slow-moving, but less-intense system made landfall on the east coast of Florida as a Category 2 storm with peak winds of 105 mph.

In early September, Hurricane Ivan developed just south of where Frances formed, intensifying quickly. Moving through warm ocean waters, the storm reached Category 5 strength three separate times before making landfall as a Category 3 hurricane along the Mississippi/Alabama border.

When Hurricane Jeanne made landfall in Stuart, Florida on September 26, it marked the second time in history that one state was impacted by four hurricanes in one season.

At this point 10 years ago, nine named storms had already formed in the basin, with six reaching hurricane status. In total, 2004 saw 15 named storms, nine of which became hurricanes, including 6 that reached major hurricane status (Category 3+).

While this hurricane season shares some common characteristics with the 2004 season, so far, 2014 has been relatively quiet while 2004 was the second costliest Atlantic hurricane season in history.

Hawaii Narrowly Escapes Hurricane Landfalls in the Midst of an Active Season

Hawaiians held their breath early this month as not one but two hurricanes made their way toward the islands, following similar tracks. Hurricane Iselle was the second and strongest tropical storm on record to make landfall over Hawaii’s Big Island, and though it caused localized flooding, knocked out power to thousands of homes, and took down trees, it did not cause any major damage or injuries. Iselle was followed closely by Hurricane Julio, the fourth major hurricane to form in the East Pacific Ocean so far this year, which bypassed the islands altogether. The Hawaiian Islands were spared once again.

This was not surprising. Storms such as Iselle and Julio, which tracked directly east to west from the East Pacific, typically become disorganized before reaching the islands due to the cool waters and dry air that lie to the east. Hurricanes approaching from the south represent the biggest threat to the islands, due to the warmer waters and more unstable air to the south.

Prior to Iselle, only two hurricanes had made landfall over the Hawaiian Islands since 1949. In 1959, Hurricane Dot tracked from the south and made landfall as a Category 1 storm. In 1992, Hurricane Iniki formed just inside the East Pacific and tracked west into the Central Pacific. It remained well south of the islands and then curved north, making landfall as a Category 4 storm. Both systems made landfall over the island of Kauai, located to the far west of the Hawaiian Island chain.

Nonetheless, Hawaiians and insurers should keep a watchful eye on the weather in the East Pacific. Hurricane season in the East Pacific basin, which officially runs from May 15 to November 30, has so far been characterized by above average activity with 10 named storms, 5 hurricanes, and 3 major hurricanes. The NHC’s 1971-2009 average by August 7th is 7 named storms, 3 hurricanes, and 1 major hurricane.

Activity in the Central Pacific is closer to normal levels. According to the CPHC, between 1971 and 2013, an average of four or five tropical cyclones were observed in the region each hurricane season, which runs from June 1 to November 30. Activity ranged widely from no cyclones in 1979 to as many as 11 cyclones in 1992 and 1994.

While it is rare for hurricanes to make landfall in Hawaii, events such as Iselle and Julio are a reminder that even in paradise there is potential for natural catastrophe loss.

2014 Atlantic Hurricane Season Outlook: Are the Tides Beginning to Turn?

The 2014 Atlantic Hurricane Season officially kicked off this week (June 1), running through November 30. Coming off a hurricane season with the lowest number of hurricanes in the Atlantic Basin since 1983, will 2014 follow suit as a less active season? If so, is the Atlantic Basin officially signaling a shift out of an active phase of hurricane activity? Or will we revert back to the above-average hurricane numbers and intensities we’ve grown accustomed to over most of the last 20 years? And regardless of the season’s severity, what should be done to prepare?

Forecasting the 2014 Hurricane Season

Most forecasts to date, including those of Colorado State University and the National Oceanic and Atmospheric Administration (NOAA), are calling for an average to below-average season in terms of the number of named storms (8–13), hurricanes (3–6), and major hurricanes (0–3). The same holds true for the overall intensity forecasts, where projected seasonal values of Accumulated Cyclone Energy (ACE) range from just 55 to 84, compared to the average overall seasonal ACE of 101.8.

So what’s driving this outlook? Most forecasting organizations are attributing it to two major atmospheric drivers that have been known to suppress hurricane activity: the strong likelihood of an El Niño event developing this summer into the peak part of the season from July through October, and below-average sea surface temperatures in the Atlantic Basin’s Main Development Region (MDR).

Model forecasts for El Niño/La Niña conditions in 2014. El Niño and La Niña conditions occur when sea surface temperatures in the equatorial central Pacific are 0.5°C warmer than average and 0.5°C cooler than average, respectively.

Model forecasts for El Niño/La Niña conditions in 2014. El Niño and La Niña conditions occur when sea surface temperatures in the equatorial central Pacific are 0.5°C warmer than average and 0.5°C cooler than average, respectively.

El Niño conditions create stronger-than-normal upper-level winds, which inhibit storms from forming and maintaining a favorable structure for intensification. Similarly, below-average ocean temperatures in the MDR essentially reduce the energy available to fuel storms, making it difficult for them to develop and intensify.

However, low activity does not always translate into a decrease in landfalling hurricanes. Also, all it takes is one landfalling event to cause catastrophic losses. For example, 1992 was a strong El Niño year, yet Hurricane Andrew made landfall in Florida as a Category 5 storm, eventually becoming the fourth most intense U.S. landfalling hurricane recorded, and the fourth costliest U.S. Atlantic hurricane. Of course, while a landfalling storm like Andrew may have occurred during the last significant El Niño year, there’s no guarantee it will happen this season. The U.S. has not experienced a major landfalling hurricane since Hurricane Wilma in August of 2005. This eight-year drought is the longest in recorded U.S. history.

Preparing for Hurricane Season

Whether or not the 2014 Atlantic hurricane season is active, it is imperative to monitor and prepare for impending storms effectively to help reduce the effects of a hurricane disaster.

The NOAA National Hurricane Center provides several tips and educational guides for improving hurricane awareness, including forecasting tools that assess the potential impacts of landfalling hurricanes. This year, NOAA also offers an experimental mapping tool, as well as other new tools, to help communities understand their potential storm surge flood threat.

The RMS Event Response team provides real-time updates for all Atlantic hurricanes, among other global hazards, 24 hours a day, seven days a week. Similarly, when it comes to preparation, along with the essentials, such as bottled water, canned foods, and battery-powered flashlights, consider purchasing these ten items.

Are you ready for the 2014 Atlantic Hurricane season?