A new Gallagher Re report has indicated that the March 15–16 severe convective storm (SCS) outbreak is on track to become the second U.S. SCS event of the year to generate more than $1 billion in industry losses, occurring within the span of a single week, following the hail and tornado-driven impacts of the March 10–12 outbreak.
According to the firm, the latest SCS outbreak impacted the central and eastern United States and was accompanied by historic late-season snowfall across the Northern Plains and Midwest.
As mentioned, Gallagher Re expects insured losses from the event to settle at a minimum of around $1 billion, with the potential to rise even higher, while the overall direct economic cost will be at least 25% greater once uninsured or underinsured assets and other losses are included.
“After a highly manageable and quiet start to the year for US SCS activity and subsequent losses, as the calendar turned to March, it initiated considerable storm genesis. There have now been notable outbreaks on March 4, March 5–7, and March 10–12,” the reinsurance broker’s report added.
Gallagher Re explained that this year is not unique in experiencing a highly active March, as the month has consistently featured widespread damaging activity since 2023.
The firm’s report went on to note that last year, the Mid-March Tornado Outbreak became the costliest event of the season with insured losses reaching $8.5 billion in today’s dollars. March 2025 also set a record for the most tornadoes in March, with at least 239.
Gallagher Re continued, “March is known as the historical start to “peak” SCS season in the United States. The peak months for overall SCS activity and observed losses are March, April, May, and June.
“Since 2010, those four months have accounted for at least 72% ($390 billion) of US SCS insured losses. On an annual basis, the US has now seen three consecutive years of minimal $50 billion in SCS-related insured losses.”
In related news, Swiss Re recently disclosed that although global insured losses in 2025, at $107 billion, fell below the long-term natural catastrophe trend, secondary perils, including wildfires, SCS and floods, accounted for a record 92% of the total.
