US Severe Convective Storm Losses Top $35B as the August Derecho Outruns 2026 Cat Budgets

US severe convective storms have generated more than $35 billion in insured losses through August 14, 2026, after an early-August derecho tore across the Chicago metro and the Ohio Valley (Gallagher Re, August 2026). Six weeks earlier the figure was $22 billion.

That already ranks as the sixth-most-expensive SCS year on record, built from at least six separate multi-billion-dollar outbreaks rather than one storm that trips a single reinsurance layer.

Key Takeaways

• $22 billion at mid-June became more than $35 billion by August 14, with roughly $8 to $13 billion arriving in five weeks. A quiet mid-year read is not evidence that the loss will not arrive.
• Six separate multi-billion-dollar outbreaks so far, trailing only 2023 with 11, 2024 with 10 and 2025 with 7 on the same measure.
• Individual 2026 events mostly landed in the $1 billion to $5 billion range, under the per-occurrence retentions large national carriers carry, so most of the total accumulates against net retention.
• 43.5 million US properties now carry moderate or greater hail risk, representing roughly $17.84 trillion in reconstruction cost value.

A Quiet First Half, Then Six Weeks of Acceleration

Gallagher Re's mid-year read, published June 18, put year-to-date US severe convective storm insured losses at $22 billion, tracking behind the elevated pace of 2023 through 2025 (Gallagher Re, June 2026). Aon's H1 tally put US SCS losses at roughly $27 billion for the first half, notably below the $40 billion-plus recorded in the first halves of 2023, 2024 and 2025. Both brokers described a season that looked, at the halfway mark, below trend.

The August derecho reset the year. Gallagher Re describes "a high-end derecho event" that produced "significant damage across the Chicago (IL) metro region and other notable population centers in Indiana, Ohio, and Kentucky." Winds approached 90 miles per hour through Chicago's south suburbs and northwest Indiana, the outbreak spawned 11 tornadoes including an EF-2 with peak winds of 115 miles per hour that tracked more than 25 miles, and more than 1.1 million customers lost power (Insurance Business, August 2026).

Illinois alone has recorded more than 200 confirmed tornadoes year to date, past its full-year 2024 count of 142 and running at roughly four times its long-term average. Guy Carpenter's early read placed the single August outbreak among the ten costliest US SCS events since 1995, a list whose tenth-ranked entry, from 2014, cost the industry $5.1 billion.

Year	Full-year US SCS insured losses	Multi-billion-dollar outbreaks
2023	$63B	11
2024	$64B	10
2025	$51B	7
2026 (through Aug 14)	$35B+	6+
2021-2025 average	~$50B	—

Against full-year totals of $63 billion in 2023 and $64 billion in 2024 (Insurance Journal), and $51 billion in 2025 (Swiss Re Institute, sigma 1/2026), the 2021 to 2025 five-year average for the peril lands near $50 billion.

Why an Accumulating Peril Strains a Cat Budget Differently

A hurricane makes landfall once, generates one occurrence date, and either pierces a per-occurrence catastrophe attachment or it does not. Severe convective storm losses arrive as a sequence of discrete, geographically scattered events, each individually well below the size that would trigger a per-occurrence recovery but collectively large enough to erode an aggregate deductible or an annual aggregate limit over a year.

That is why $35 billion of industry loss can leave most of the total sitting on primary balance sheets. Moody's Ratings is explicit that "insurers will continue to retain a large proportion of losses from secondary perils," a function of reinsurers holding attachment points calibrated to keep frequency-driven perils inside the cedant's net retention.

Frequency erosion, not single-event severity, is the variable a cat budget has to track through a season. An aggregate layer with $200 million of remaining capacity in January can arrive at August with a fraction of that cushion left, purely from a string of sub-threshold events that never individually looked large enough to flag. Some aggregate catastrophe bond transactions covering the SCS peril had attachment levels eroded by winter storm losses earlier this year, so the derecho landed against layers with less remaining capacity than a clean year would have left them.

Allstate's March disclosure shows the primary-side version of the same arithmetic: $925 million of March catastrophe losses inside $1.24 billion for the first quarter, spread across 15 separate wind and hail events, none large enough on its own to be the story (Q1 SCS signal). Reinsurers met the dynamic at mid-year by restructuring rather than repricing, with 20% to 25% property catastrophe rate reductions alongside aggregate, multi-year and multi-line covers attaching where cedants can actually use them (Gallagher Re July 2026 First View).

Hail Develops Slower Than the Headline

The $35 billion is a preliminary industry estimate, and hail claims are among the slowest-developing property lines to move from initial reserve to final paid. Hail does not produce visible damage the way a tornado produces visible structural damage. Homeowners frequently do not notice or report it for weeks or months, and the claims then queue behind roofing contractors and independent adjusters working the same geography at the same time.

The exposure sitting behind that lag has grown materially. 43.5 million US properties now carry moderate or greater risk from damaging hail, roughly $17.84 trillion in reconstruction cost value (Cotality, 2026 Severe Convective Storm Risk Report). The US recorded 142 days with damaging hail in 2025, against a 20-year average of 122, and more than 235,000 Texas homes took damaging hail that year alone.

Cotality puts the insured-loss potential of a single severe hail event at nearly $30 billion, comparable to a major hurricane landfall. That matters for reserving because a hail book can now produce a hurricane-scale tail loss without a hurricane forming, developing on the contractor-availability timeline rather than the faster wind-and-surge one. Loss development factors selected against pre-2020 hail and wind accident years will understate the 2026 tail for as long as adjusting and repair capacity in greater Chicago and the Ohio Valley corridor stays constrained relative to claims filed.

The anchor itself is moving. Swiss Re found the number of SCS events causing average annual losses of $1 billion or more was 59% higher in the five years to 2025 than in the five years to 2020. A cat budget or an aggregate structure anchored to a $50 billion five-year average understates the peril for the same reason 2026's own total climbed from $22 billion to $35 billion in six weeks.