The 2024 Atlantic hurricane season, which officially drew to a close on 30 November, will be remembered as one of extremes, marked by record-breaking storms and unprecedented weather patterns. So, how did the season unfold, and what are the key lessons for the insurance industry?
This highly active season produced 18 named storms and 11 hurricanes, five of which made landfall in the US, causing widespread destruction and tragic loss of life.
At the outset, exceptionally warm North Atlantic sea surface temperatures led to alarming predictions of one of the most active seasons on record. These forecasts seemed justified in July, when Hurricane Beryl became the earliest Category 5 hurricane on record.
In August, Hurricane Debby followed, its remnants triggering heavy rainfall across the eastern US along with catastrophic flooding in Quebec that resulted in the region’s costliest severe weather event, with damages exceeding C$2.5bn ($1.8bn).
However, the season’s tempo shifted dramatically in mid-August, with a surprising lull that marked the quietest period since 1968. Storm formation was suppressed by Saharan dust and unfavourable wind conditions.
Activity surged again in late September and October, culminating in hurricanes Helene and Milton – both supercharged by record-high sea surface temperatures and responsible for the year’s largest insured losses. Remarkably, this was only the third time in over a century that Florida experienced two major hurricane landfalls in a single season (previously in 1906 and 2004).
Despite the mid-season calm, the year added to a troubling trend: insured losses from natural catastrophes exceeded $100bn globally for the fifth consecutive year. What lessons can the insurance industry take from this volatile season?
1. The growing threat of rapid intensification
Seven storms this season experienced rapid intensification, including Hurricane Milton, which strengthened by over 90 mph within 24 hours – one of the fastest recorded. This trend complicates forecasting and leaves communities with less time to prepare, increasing the likelihood of higher losses.
For insurers, close monitoring of this phenomenon is critical. It underscores the need for better predictive models and proactive strategies to mitigate claims from unprepared or under-resourced regions.
2. Growing risks facing inland areas
Hurricane Helene revealed the growing risk to inland areas, where building codes are often less stringent than along the coast.
While Helene made landfall as a Category 4 storm in Florida’s Big Bend region, the most severe impacts occurred 500 miles inland in Georgia, where wind gusts of 100 mph caused extensive damage. Older building stock and less robust construction standards exacerbated the destruction.
Helene’s far-reaching impact exposed the vulnerability of inland areas. Modern wind speed designs for buildings in Tampa are 132 mph, but drop to 105 mph in Albany, Georgia.
For insurers, this highlights the importance of granular portfolio analysis, particularly regarding property age and resilience. Enhanced data collection on building standards and risk exposure in inland areas will be essential as these regions face increasing storm intensity.
3. The rising cost of flooding
Flood-related losses stood out as a significant concern this season. Hurricane Helene’s remnants dumped nearly three-quarters of a metre of rain over North Carolina’s Appalachian region, causing severe flooding. A World Weather Attribution study attributed 10 percent of the rainfall to human-induced climate change.
Flooding presents unique challenges for insurers, especially in markets like the US, where many residential policies exclude flood damage, leaving homeowners reliant on the National Flood Insurance Program.
As hurricane-induced flooding becomes more frequent, insurers must navigate the growing complexity of disentangling flood-related claims from wind damage.
Looking ahead
Despite officially drawing to a close, the hurricane season is far from over yet. As this year’s activity attests, the increasing unpredictability of extreme weather means it is too soon to breathe a sigh of relief yet. Furthermore, with record-breaking sea surface temperatures likely to persist, insurers and communities must prepare for greater challenges in 2025.
Adapting to these lessons will be essential for building resilience, refining risk models, and reducing future losses. Staying one step ahead of the weather remains a formidable but necessary goal.
David Wilkie is a senior research analyst in MS Amlin’s exposure management team.