In a hurricane claim, the question of whether interior water damage came from wind-driven rain or rising water usually determines who pays, and sometimes whether anyone pays at all. Standard homeowners and commercial property policies cover windstorm, including rain that enters through an opening the storm created, but exclude flood and storm surge. Flood coverage lives in a separate contract, most often the National Flood Insurance Program's Standard Flood Insurance Policy (SFIP), which insures only "direct physical loss by or from flood." Same building, same night, two policies, two burdens of proof. This article maps the causation doctrines that govern the dispute, the controlling Gulf Coast decisions, and the evidence that actually wins these cases.
Two policies with mirror-image burdens
Under an all-risk homeowners or commercial form, the insured proves a direct physical loss during the policy period, and the burden shifts to the insurer to prove an excluded cause such as flood. The SFIP runs the other way. It is a single-peril contract, so the insured bears the burden of proving the loss was caused by flood as the policy defines it.
That structure creates the gap policyholders fall into. The wind carrier can attribute the damage to surge and rest on its exclusion. The flood carrier can attribute the same damage to wind and argue the insured never carried its burden. Neither carrier has to disprove the other's theory, and nothing in either contract forces them to agree.
The SFIP adds its own traps. It is administered under federal law, it states on its face that it is not a valued policy, its sworn proof of loss deadline (60 days unless FEMA extends it) is strictly enforced, and courts have barred recovery for late or noncompliant filings even where the carrier investigated the claim or made partial payments, and suit must be brought in federal district court, where state bad faith remedies are generally unavailable. An adjuster or attorney who treats the flood claim like a state law homeowners claim will lose rights without noticing.
Anti-concurrent causation clauses and the Leonard framework
Most property forms now lead their exclusions with anti-concurrent causation (ACC) language: the insurer will not pay for loss caused directly or indirectly by an excluded peril "regardless of any other cause or event contributing concurrently or in any sequence to the loss." The Fifth Circuit gave that language its defining reading in Leonard v. Nationwide Mutual Insurance Co., 499 F.3d 419 (5th Cir. 2007), a Hurricane Katrina case from Pascagoula, Mississippi. The court sorted hurricane damage into three categories: damage caused only by wind is covered, damage caused only by water is excluded, and damage caused by wind and water acting together falls within the ACC clause and is excluded. The same year, in Tuepker v. State Farm Fire & Casualty Co., 507 F.3d 346 (5th Cir. 2007), the Fifth Circuit confirmed that storm surge is "flood" under the water damage exclusion even though wind pushes it ashore.
Read literally, Leonard's third category threatens to swallow the first. The Mississippi Supreme Court pushed back in Corban v. United Services Automobile Association, 20 So. 3d 601 (Miss. 2009), a unanimous decision holding that an ACC clause does not reach losses caused by wind and water acting in sequence on the property. Once wind damages part of a structure, the insured's right to recover for that damage vests, and surge arriving later does not erase it. The clause only bars recovery where the two perils combine at the same time to produce an indivisible loss. The practical effect was to convert many coverage-killing disputes into allocation disputes, which is where most hurricane litigation now lives.
Texas puts the allocation burden on the insured
Texas adds a doctrine adjusters on the western Gulf cannot ignore. Under the state's concurrent causation doctrine, when covered and excluded perils combine to cause a loss, the insured must offer evidence giving the factfinder a reasonable basis to allocate the damage between them. Fail to segregate, and the claim fails, even if everyone agrees some of the damage was covered.
JAW The Pointe, LLC v. Lexington Insurance Co., 460 S.W.3d 597 (Tex. 2015), a Texas Supreme Court case arising from Hurricane Ike in Galveston, shows how harsh that combination can be. Wind damage was covered and paid; flood damage was excluded. The fight was over ordinance compliance costs after the city required demolition and rebuilding. Because the city acted on the combined wind and flood damage, and the ACC clause excluded loss caused even indirectly by flood, the court held the ordinance losses were excluded. It did not matter that the wind damage alone might have been enough to trigger the ordinance; what mattered was what actually triggered it.
The doctrine's edges remain unsettled. The Fifth Circuit certified allocation questions to the Texas Supreme Court twice in two years, in Frymire Home Services in 2021 and in Overstreet v. Allstate in 2022, asking among other things whether an insured who contends a covered peril caused 100 percent of the loss still bears a segregation burden. Both cases settled before the court could answer, so the gaps Judge Willett flagged in Overstreet are still open.
Florida's default favors coverage, but the clause controls
Florida starts from the opposite presumption. In Sebo v. American Home Assurance Co., 208 So. 3d 694 (Fla. 2016), the Florida Supreme Court applied the concurrent cause doctrine to an all-risk loss where covered perils (hurricane wind and rain) combined with an excluded one (defective construction) and no single efficient proximate cause could be identified. Where independent perils combine and at least one is covered, the loss is covered, unless the policy says otherwise.
That last clause does real work. Florida courts enforce ACC language, and federal courts applying Florida law said even before Sebo that parties may contract around the concurrent cause doctrine, as the Middle District of Florida held in Paulucci v. Liberty Mutual Fire Insurance Co., 190 F. Supp. 2d 1312 (M.D. Fla. 2002). So the Florida analysis begins with the wording of the specific exclusion. If it carries ACC language, the case looks like Leonard. If it does not, Sebo's coverage-friendly default applies. The Sebo policy itself turned on exactly that distinction: some exclusions had ACC language, the operative one did not.
Wind-driven rain has its own wrinkle. Most forms cover interior rain damage only if wind first created an opening in the roof or walls. An adjuster who documents the opening, or its absence, has usually decided the claim.
The dual-carrier squeeze and the COASTAL Act's partial fix
When the wind carrier says flood and the flood carrier says wind, no statute forces a joint adjustment, and the two adjusters rarely coordinate. Congress addressed the most extreme version of the problem, the Katrina-era "slab case" where nothing remains to inspect, in the COASTAL Act of 2012, codified at 42 U.S.C. § 4057 and signed July 6, 2012. For these "indeterminate losses," NOAA produces post-storm hindcast assessments through a Named Storm Event Model showing the strength and timing of wind and water at a given location, and FEMA may apply an allocation formula, but only if NOAA certifies the assessment is at least 90 percent accurate for that site. The act is narrow. It applies to total destruction cases, it expressly creates no cause of action, and it leaves the ordinary partial loss exactly where it was: the parties must prove causation building by building.
Building a causation record that holds up
Timing is the whole case. Hurricane winds typically arrive before peak surge, so the first task is fixing when each peril reached the risk: National Weather Service observations, airport station data, tide gauges, and surge hindcasts, including the NOAA post-storm assessments the COASTAL Act now generates. Then match the physics to the building. Exterior watermarks and mud lines mark the flood's ceiling; staining that starts at the roofline or ceiling and runs down points to wind-created openings; damage above the waterline cannot be flood. Photograph before remediation, keep the removed roofing and drywall, and compare neighboring structures at different elevations.
On the claim side, file both claims immediately and protect the SFIP proof of loss deadline even if the flood carrier looks like the wrong target, because that deadline will not wait for the carriers to finish pointing at each other. And in litigation, obtain both carriers' adjustment files. Two insurers taking flatly inconsistent causation positions on the same loss is evidence a jury understands without expert help.
Sources
- Leonard v. Nationwide Mutual Insurance Co., 499 F.3d 419 (5th Cir. 2007)
- Tuepker v. State Farm Fire & Casualty Co., 507 F.3d 346 (5th Cir. 2007)
- Corban v. United Services Automobile Association, 20 So. 3d 601 (Miss. 2009)
- JAW The Pointe, LLC v. Lexington Insurance Co., 460 S.W.3d 597 (Tex. 2015)
- Sebo v. American Home Assurance Co., 208 So. 3d 694 (Fla. 2016)
- Paulucci v. Liberty Mutual Fire Insurance Co., 190 F. Supp. 2d 1312 (M.D. Fla. 2002)
- Frymire Home Services, Inc. v. Ohio Security Insurance Co., 12 F.4th 467 (5th Cir. 2021), certified questions
- Overstreet v. Allstate Vehicle & Property Insurance Co., certified questions (5th Cir. May 19, 2022)
- 42 U.S.C. § 4057, Alternative loss allocation system for indeterminate claims (COASTAL Act)
- FEMA, Standard Flood Insurance Policy, Dwelling Form
- NOAA, COASTAL Act overview and Named Storm Event Model
- Robins Kaplan, Flood Exclusions and Determining Cause of Loss After Sebo
- Hunton Andrews Kurth, Causation Issues to Consider as You Prepare Your Hurricane Ian Insurance Claim
- Thompson Coe, Concurrent Causation Is Key in Texas Storm and Hurricane Insurance Suits
- Thompson Coe, Hurricane Harvey: Anti-Concurrent Causation Revisited
- Butler Snow, Flood Claims Under the SFIP: How Failing to Comply with Strict Policy Deadlines Can Sink Your Flood Claim
- Ward and Smith, Pitfalls of NFIP Flood Insurance Policies
- Bloomberg Law, Insurance Settlement Leaves Gaps in Texas Causation Doctrine
- Claims Journal, Key Mississippi Katrina 'Wind v. Water' Case Settled Out of Court