Diving into 2024 hurricane season

Hurricanes are typically the biggest and most costly disasters that the US faces each year. And the coming hurricane season is set to be ‘supercharged’ by warm oceans and the “La Niña” weather event, with more, and more violent storms predicted.

Now is the best time to make sure your clients are covered for June 1st. We caught up with FloodFlash lead structurer and catastrophe analyst Henry Bellwood to discuss all things hurricanes. Get clued up on what’s coming below…

Chris Sills: What is a hurricane?

Henry Bellwood: Hurricanes are large tropical cyclones specific to the Atlantic basin that move in a clockwise motion in the northern hemisphere due to the rotation of the earth. Their fundamental driving power is energy from the ocean and the moisture close to the waters surface. As the storms move west across the tropics, they suck heat and water to power ferocious events.

Hurricanes are large tropical cyclones that can cause significant damage, and the 2024 season is predicted to be supercharged.

CS: When is hurricane season?

HB: What we label as hurricane season has changed over time. The first mention of hurricane season came in 1700 and was suggested to be in July, August, and September. Modern hurricane season is longer, beginning at the start of June, ending at the close of November.

CS: Why is this hurricane season set out to be one of the worst?

HB: There are a couple of factors here. For me, the most important is the all-time record highs we are seeing in terms of sea temperatures. Sea surface temperature is considered the key driver in Hurricane formation. Warmer seas contain more energy. And more energy produces more energetic storms. This isn’t a guarantee of a bad hurricane season. There is always an element of chance, particularly on where/if the storms make landfall. However, with this year’s temperatures sitting so far above the norm, we don’t really know how bad it could get.

The other (related) pattern is the La Niña weather pattern that occurs every 2-7 years. This is forecast to develop in June-August in 2024, suggesting that the second half of hurricane season will be more active with increased likelihood of disruptive weather systems. La Niña not only increases the number of hurricanes that develop, it also allows stronger hurricanes to form. Most experts agree that strong El Niño patterns lead to greater impacts from La Niña. This is the case for 2024 and a reason for any risk manager to be particularly wary ahead of June 1st.

CS: Can you explain how storm surges work and what the impact is?

HB: Hurricanes are systems of rotating moisture and wind around a central point of very low pressure. They build up power over water (the Gulf and Atlantic) before unleashing it when making landfall. The low pressure causes a bulge of raised water that can wash over land at fast speeds, known as storm surge. The main danger of storm surge is the sheer energy of the water. Storm surges can rip buildings from foundations, and hurl debris like cars, boats and trees through the towns and cities they impact. Where assets aren’t completely destroyed by a surge, the salt water corrodes physical assets and complicates the restoration of impacted sites, leading to larger claim values.

What about extended, intense rain?

HB: Rainfall intensity is rarely more extreme than after the landfall of a hurricane. The huge amounts of ocean water collected by the storm is dumped once it begins to lose its energy over land. Hurricane Harvey is one of the most severe examples of what some scientists call “stalled storms”. This is where the storms move slowly or even stop over a specific area. This can be particularly devastating over metropolitan areas. According to the National Weather Service, parts of Texas experienced 60 inches of rainfall, causing massive flooding across the state.

Hurricanes can bring huge amounts of intense rainfall that, when coupled with urbanisation and poor drainage systems, can lead to significant damage.

CS: Where is most at risk?

HB: Coastal towns along the East and Gulf coasts are naturally most at risk from storm surge, however towns upstream of the coast can be severely inundated if a storms path leads in such a direction, especially if along a river. From a rainfall perspective, coastal towns see a significant proportion of this rain, but states as far north as Illinois and Indiana have been known to see this extreme rain dropped on their doorstep – such as with Hurricane Ike. During Ida, despite landfall in Louisiana it then moved to dump unprecedented post-hurricane rainfall in New England and Canada.

CS: Is climate change having an impact?

HB: This specific quality of far reaching rain seems to have been heightened during events of the last decade, with experts concerned that this may be caused by greater moisture retention of the atmosphere caused by climate change. What’s clear is that many regions with no lived experience of flooding may see such rainfall in the decades ahead – posing questions about how well prepared, or how vulnerable, such regions may be. Whatever the case, Hurricanes happen already, so concerns about the future climate shouldn’t stop businesses and communities from preparing for the very next storm.

CS: How can FloodFlash support clients at risk?

HB: Wind parametric has been widely available for some time, however its only since FloodFlash launched in 2023 that US businesses and public entities can access a fully customisable flood parametric option which guards against the rain and surge damage caused by hurricanes. The best risk managers will look to combine wind and flood parametric: wind for high category hurricanes causing damage to roofs, windows, exterior walls etc, and flood coverage for storm surge and catastrophic rainfall causing property contents and equipment damage at lower levels as well as business interruption.

This is going to be an important topic this year so expect to see more about the biggest threat to US communities. There are many businesses and public entities that don’t have coverage for their risk, and time is running out to place it.


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