Atlantic – Seasonal Activity and Hurricane Isaias

During the final stages of the Atlantic hurricane season, tropical cyclone activity typically shifts away from the main development region in the tropical Atlantic towards the Caribbean Sea, the Gulf of Mexico and the waters off the US East Coast. This seasonal shift is one of the most predicable and consistent features of Atlantic tropical cyclone activity. Despite the broader influence of El Niño, the 2026 season appears to be following this established pattern.

Major Hurricane Isaias, the only storm to reach hurricane strength during the 2026 Atlantic hurricane season, formed in the western Gulf of Mexico on 6 October. After weakening from its peak intensity, Isaias made landfall near Destin, Florida, late on 9 October as a Category 2 hurricane. Modelled estimates have consistently indicated insured losses in the low single-digit billions of US dollars.

For ILS investors, it is important to recognise that, historically, at these relatively modest loss levels, modelled estimates have provided a useful indication of the potential magnitude of industry-wide losses but have been less reliable in predicting ultimate losses reported by Property Claim Services (PCS) or the impact on individual cedent. At this stage, no officially confirmed loss figures are available, and estimates remain subject to uncertainty.

Atlantic

The short-lived sub-tropical storm Josephine briefly attained sub-tropical storm status on 21 October off the northeastern US coast before transitioning into a powerful extra-tropical low-pressure system late on 22 October. Josephine brought nor’easter-like conditions to the northeastern US and eastern Canada. No significant insurance or reinsurance impacts are expected.

Eastern Pacific

Tropical cyclone activity in the Eastern Pacific continues to dominate the 2026 season. Over the past two weeks, Major Hurricane Trudy and the developing Hurricane Vance have both posed potential threats to Mexico’s Pacific coast. According to the latest forecasts, Vance could intensify into a major hurricane early on Saturday. However, it is expected to weaken below major hurricane strength before its closest approach to, or potential landfall along, Mexico’s west coast. No significant insurance or reinsurance impacts are currently anticipated.

Western Pacific

Super Typhoon Champi, which reached the equivalent of Category 5 intensity, is weakening ahead of its expected passage north of Taiwan over the weekend. Storm conditions are anticipated across northeastern Taiwan. Champi is subsequently forecast to affect Kyushu in southern Japan later next week, potentially as a tropical storm or tropical depression. While heavy rainfall and localised flooding remain possible, no significant insurance or reinsurance impacts are currently expected.

As always, Twelve Securis continues to closely monitor any catastrophe events and will issue specific updates on any relevant new major events which occur.

Please feel free to contact us with any questions.