An important update since this series launched: El Niño is no longer a probability to monitor. It is a developing event. IRI's May 2026 forecast puts the El Niño probability at 98% for this summer, with a 97-98% chance persisting through early 2027. The spring predictability barrier is behind us. The models are aligned. The question is no longer whether El Niño arrives. It is how strong it gets. NOAA's May update puts a 37% probability on a super El Niño peak this winter, up from 25% last month. The ECMWF is calling it near certainty. Subsurface heat content in the equatorial Pacific is currently running more than double what it was at the same point during the 2023-24 event.
Before the geography, the baseline numbers. El Niño is not a weather event. It is a multi-year economic forcing mechanism.
|
El Nino Event |
Direct US Economic Loss |
Global GDP Drag (3-Year Lag) |
Source |
|
1997-98 (Strong) |
~$4 billion |
$2.1 Trillion |
Nature Communications, Sept 2023 |
|
2015-16 (Strong) |
Included in the global figure |
$3.9 Trillion |
Nature Communications, Sept 2023 |
|
2023-24 (Moderate-Strong) |
Part of the $108B global |
Record 142 nat. cat. events |
Swiss Re Institute Sigma 1/2024 |
If the current subsurface heat trajectory holds and this event approaches the 1997-98 magnitude, the economic forcing numbers in the table above are the relevant order of magnitude for what follows.
A 2023 study in Nature Communications found that losses compound through cross-sector and cross-border spillovers for three or more years after the event year. The contemporaneous loss from the 2015-16 event was $739 billion in the occurrence year alone. The three-year cumulative total reached $3.9 trillion.
At the insured-loss level, the Swiss Re Institute reported a record 142 natural catastrophes, resulting in $108 billion in global insured losses in 2023, a year marked by the mid-year La Niña-to-El Niño transition. Global natural catastrophe insured losses reached $137 billion in 2024, on a long-term trend of 5-7% annual increase in real terms.
NOAA AOML | U.S. Economic Loss Baseline, 1980-2024
Droughts: ~$368 billion in U.S. economic losses. Inland flooding: ~$293 billion in damages. ENSO is a primary driver of both. Future NOAA SPEAR model research shows extreme droughts becoming more common in the Southwest and extreme floods more common in the Southeast and Northeast as ENSO amplitude increases.
The peril map does not shift uniformly. Here is the territory-by-territory breakdown for a 2026 El Niño event.
California and the Southwest | Flood, Mudslide, Post-Wildfire Debris Flow
During El Niño, the North Pacific jet stream shifts south, driving above-normal precipitation across California and the Southwest. The 2023-24 cycle demonstrated this pattern clearly: above-average rainfall overwhelmed urban drainage systems, and Sierra foothills and coastal regions faced flash floods and significant mudslides.
The exposure that most carriers underestimate is the wildfire-to-mudslide chain. Burn scars from previous fire seasons dramatically increase the risk of debris flows when heavy precipitation arrives. Properties that survive a wildfire one year sit in high-risk debris flow corridors the next winter under El Niño conditions. This is one of the most underpriced secondary peril sequences in U.S. property insurance.
Gulf Coast and Southeast | River Flooding and Severe Convective Storm
El Niño generally brings above-average precipitation to Florida and the Gulf Coast during fall, winter, and spring. Storm tracks shift farther south on average, producing more clouds, rain, and severe weather.
Florida River Flooding Frequency | NOAA NWS Southeast River Forecast Center (1975-2006 data)
Florida river flood events average 23.3 per year during strong El Niño phases. During neutral ENSO conditions: 4.9 events per year. That is nearly a fivefold increase in a single state. The majority of river-flooding events occur during strong El Niño phases.
Less than 2% of households in Georgia are currently covered by the National Flood Insurance Program. Swiss Re Institute data show that economic losses from Hurricanes Helene and Milton in 2024 were more than double the insured losses, at $113 billion in economic losses vs. $44 billion in insured losses. The protection gap, not storm frequency, determines what this costs the industry.
East Texas, Louisiana, and Mississippi | Anomalous Fire Risk
This is the counter-intuitive one. The National Interagency Fire Center's March 2026 monthly outlook flags concerns about an active summer fire season in the pine-dominant areas of east Texas, Louisiana, and Mississippi if El Niño sets in rapidly, similar to patterns seen in 2023.
Southeast fire risk is traditionally priced as secondary. El Niño can quickly reprice that assumption under the right fuel and weather conditions. Carriers with significant commercial timber or rural residential exposure in these states should be tracking this scenario.
Atlantic Hurricane Season | Moderated, Not Eliminated
El Niño creates increased wind shear over the Atlantic Basin, which suppresses hurricane development. Multiple forecasters, including AccuWeather and the EURO seasonal model, are projecting that the 2026 Atlantic hurricane season could see the fewest storms since 2015 if El Niño forms as projected.
Do not treat this as a margin offset. Hurricane Ian in 2022 caused $113 billion in economic losses in a below-average activity year. One storm is sufficient. The Eastern Pacific hurricane season runs countercyclically to the Atlantic, and El Niño enhances Eastern Pacific storm activity, affecting Hawaii, Mexico, and U.S. Southwest coastal markets.
The Bottom Line on Hurricane Suppression
A quieter Atlantic season reduces the highest-probability catastrophe scenario for Gulf and East Coast carriers. It does not eliminate it. And it does not offset the flood and wildfire exposure that El Niño adds elsewhere. Do not net these risks against each other in your aggregate planning.