The Dance of the Cyclones

On August 7, 2017, powerful Typhoon Noru made landfall in Japan, lashing the island nation with heavy rainfall and maximum sustained winds near 75 mph.  While the dangers associated with Noru ought not to be underestimated, there is a sigh of relief, considering that last week, media outlets worldwide characterized Noru as the “Earth’s strongest storm of 2017.”

What had happened for Noru to achieve such notoriety?  After its birth on July 20, 2017, Noru roamed the Pacific Ocean at a strength equivalent to a Category 1 Hurricane in the Atlantic Basin.  However, roughly four days later, Noru encountered Tropical Storm Kulap, causing the two systems to engage in what experts call the “Fujiwhara effect.”  After dancing around each other, Noru—the stronger and bigger of the two systems—simply swallowed Kulap, resulting in a much more potent storm.  After engaging in this dance with Kulap, Noru crossed over its path from earlier in the week and began heading towards southern Japan.

In layperson’s terms, what is the Fujiwhara effect?  Discovered in the 1920s by Sakuhei Fujiwhara, a Japanese researcher and meteorologist, the Fujiwhara effect—or, Fujiwhara interaction—explains a phenomenon where two tropical cyclones less than 900 miles apart rotate about a common midpoint.  As a result of this movement, the distance between the two vortices decreases.  Depending on the size of the systems, as these severe weather patterns circle each other, they have the potential to merge into one storm.  Usually, the bigger system will absorb the smaller system.  Noru and Kulap engaged in this merry-go-round-like weather pattern around July 24, 2017.  However, it is also possible that this binary interaction might deflect the original path of one, or even both, of the systems. 

This graphic explains the Fujiwhara effect:

How common is the Fujiwhara effect?  The Fujiwhara effect is relatively well documented in the annals of weather history.  More or less around the same time as Noru and Kulap engaged in their dance, tropical cyclones Hilary and Irwin engaged in a similar ritual in the eastern Pacific Basin, with Hilary’s wind shear eventually weakening Irwin.

In 1995, Hurricane Iris danced with Hurricane Humberto, before interacting with, and eventually absorbing, Tropical Storm Karen. There was also major concern back in October 2016 that Hurricane Matthew, a powerful late-season hurricane, could interact with Tropical Storm Nicole, a smaller system that formed and continued to linger in the Atlantic Basin northeast of Hurricane Matthew.  Experts feared that after engaging in their cyclonic dance, Hurricane Matthew would take aim at Florida for a second time within a few days, further devastating the area.

Superstorm Sandy, one of the largest and most costly tropical storms in the history of the United States, also experienced this effect before hitting the East Coast of the United States in late October 2012.  Sandy interacted with a low-pressure trough to its southwest that steered the storm west towards New Jersey.  Eventually the two systems merged to form the devastating “Superstorm” or “Frankenstorm” Sandy.

What are the implications for the insurance industry?  With the 2017 hurricane season in full swing—and the National Oceanic and Atmospheric Administration predicting above-normalactivity—the Fujiwhara effect plays a prominent role in severe weather patterns that the insurance industry has a vested interest in observing.  One issue to potentially consider is to what extent a system that undergoes the Fujiwhara effect changes in its meteorological makeup from the original system.  As the threat of Hurricane Matthew interacting with Tropical Storm Nicole before taking aim at Florida for a second time has demonstrated, another issue to consider is the number of occurrences.  With that said: Welcome to the dance of the cyclones!

Posted by Isabella Stankowski-Booker

Hold on to Your Hats: Another Active Hurricane Season Forecasted

Some wait for football season in the Fall while others anticipate baseball season in the Spring. Some sports fans are disappointed that basketball season just ended. But those in the insurance industry often anxiously anticipate the Atlantic Hurricane Season.

June 1 kicked off the official start of the Atlantic Hurricane Season, which incorporates property located in the North Atlantic, Gulf of Mexico, and Caribbean Sea. The season officially runs through November 30, but does not always abide by the parameters of the season’s timeline. For example, the first Named Storm of the season came early – Tropical Storm Arlene developed on April 20 in the central Atlantic region.

Like sports, the Hurricane Season has forecasters who provide watchers with guidance on what to expect this year. On May 25, 2017, the National Oceanic and Atmospheric Administration (NOAA) issued a press release outlining its 2017 Atlantic Hurricane Season outlook. The NOAA predicts that there will be 11-17 Named Storms and 5-9 Hurricanes – categorizing 2-4 as “major”. Named Storms are defined as having top winds of 39 mph or higher. A Hurricane has top winds of 74 mph or higher. And a Major Hurricane has wind speeds of at least 111 mph.

If the NOAA’s forecast is accurate, there will likely be at least 3-4 storms that will impact insured property. Hurricanes and Tropical Storms pose significant property risks – both direct and indirect. For example, high winds associated with these storms wreak havoc on roofing systems and windows, and cause damage from blown debris. The storms may stall over an area, unleashing downpours of rain and leave water with no place to go except into an insured building. And storm surge has proven to be a significant risk to property. The waves and water from a storm surge can level homes and, in extreme circumstances, reach further inland than anticipated or protected against. The over-all effect of these storms can damage local economies, affect power to neighborhoods and cities, and cause business interruption losses.

The question, therefore, is whether the NOAA’s forecast is reliable. Based on the last five years, the answer is yes. Below is a chart that compares the NOAA’s forecast with the season results:

2012 Atlantic Hurricane Season

	Predicted	Actual
Total Named Storms	9-15
Tropical Storms		9
Hurricanes	4-8	10
Major Hurricanes	1-3	2

2013 Atlantic Hurricane Season

	Predicted	Actual
Total Named Storms	13-20
Tropical Storms		11
Hurricanes	7-11	2
Major Hurricanes	3-6	0

2014 Atlantic Hurricane Season

	Predicted	Actual
Total Named Storms	8-13
Tropical Storms		2
Hurricanes	3-6	6
Major Hurricanes	1-2	2

2015 Atlantic Hurricane Season

	Predicted	Actual
Total Named Storms	6-11
Tropical Storms		8
Hurricanes	3-6	4
Major Hurricanes	0-2	2

2016 Atlantic Hurricane Season

	Predicted	Actual
Total Named Storms	10-16
Tropical Storms		9
Hurricanes	4-8	7
Major Hurricanes	1-4	4

With the exception of 2013, the NOAA’s predictions have been relatively accurate. Therefore, Hurricane Watchers should be prepared for over 10 Tropical Storms and a potentially large number of Hurricanes during this year’s Atlantic Hurricane Season.

Posted by Shannon O'Malley

What's in a Name?

The 2017 Atlantic Hurricane Season started on June 1, 2017, with one preseason storm already under our belt.  The first tropical storm, Arlene, formed on April 20, 2017, only lasted a few days and did not receive much attention.  The presence of a preseason storm also indicates that the 2017 Atlantic Hurricane Season may be particularly active.   On May 25, 2017, the National Oceanic and Atmospheric Administration (“NOAA”) issued a release advising that its Climate Prediction Center advised that the Atlantic could see another above-normal hurricane season.  Based on low-level El Niño activity, which stifles organization of storm systems in the Atlantic, the outlook is expected as follows: 

Source: www.noaa.gov/image_download/4029?itok=VoZr7icX

The early activity and several projected large storms may spur memories of seasons past where names like Andrew, Hugo, Alicia, Francis, Jeanne, Wilma, and Katrina made history and left a mark in the minds of many.  Given the immediate reaction elicited by some of these names, one may wonder why and how weather events tome to be named. 

The main purpose in naming a tropical cyclone/hurricane is to facilitate tropical cyclone/hurricane disaster risk awareness, preparedness, management, and reduction by associating each event with a name that makes it easy to understand and remember the tropical cyclone/hurricane in a region.  The shift to naming storms to assist with dissemination of information and encourage preparedness came in the United States between 1953 and 1979, during which time female first names were used to identify storms and then names associated with both genders were adopted. 

Despite a common misconception, the National Hurricane Center does not control the naming of tropical storms.  The World Meteorological Organization establishes the storm naming procedure.  For Atlantic hurricanes, there is a list of male and female names which are used on a six-year rotation. The only time that there is a change is if a storm is so deadly or costly that the future use of its name for a different storm would be inappropriate. If more than twenty-one named tropical cyclones occur in a season, any additional storms will take names from the Greek alphabet.  Tropical cyclones/hurricanes are not named after any specific person, the tropical cyclone/hurricane names selected are those that are familiar to the people in each region. 

Storm naming has other implications beyond the dissemination of tracking information.  It also affects claim adjustment preparedness.  The existence of a named storm may trigger the application of certain wind deductibles – wind/hail deductibles and hurricane deductibles.  Hurricane deductibles typically apply to hurricanes and named storms, which is when the naming of a weather event becomes a significant factor in the adjustment..  The other type of wind deductible is the wind/hail deductible which typically applies to any kind of wind-related damage.

In the United States, nineteen states and the District of Columbia have statutory hurricane definitions. One of those states is Florida where the Florida Statutes define residential “Hurricane Coverage” as follows:

(2) As used in policies providing residential coverage: 

(a) “Hurricane coverage” is coverage for loss or damage caused by the peril of windstorm during a hurricane. The term includes ensuing damage to the interior of a building, or to property inside a building, caused by rain, snow, sleet, hail, sand, or dust if the direct force of the windstorm first damages the building, causing an opening through which rain, snow, sleet, hail, sand, or dust enters and causes damage.

(b) “Windstorm” for purposes of paragraph (a) means wind, wind gusts, hail, rain, tornadoes, or cyclones caused by or resulting from a hurricane which results in direct physical loss or damage to property.

(c) “Hurricane” for purposes of paragraphs (a) and (b) means a storm system that has been declared to be a hurricane by the National Hurricane Center of the National Weather Service. The duration of the hurricane includes the time period, in Florida:

1. Beginning at the time a hurricane watch or hurricane warning is issued for any part of Florida by the National Hurricane Center of the National Weather Service;

2. Continuing for the time period during which the hurricane conditions exist anywhere in Florida; and

3. Ending 72 hours following the termination of the last hurricane watch or hurricane warning issued for any part of Florida by the National Hurricane Center of the National Weather Service. 

Fla. Stat. 627.4025(2)(a)(2016). 

According to the Insurance Service Office (“ISO”), hurricanes and tropical storms caused approximately $158.6 billion in insured losses (in 2015 dollars) in the United States from 1996 to 2015.  Therefore, understanding the implications of named storms becomes a critical component of claim management and risk projection – another form of preparedness during hurricane season. 

Posted by Anaysa Gallardo Stutzman