An ANTT force majeure claim is not won with the most sophisticated report. It is won by whoever proves, with official data, that the event exceeded what the project was designed to withstand and that the operation acted once it became aware of the risk.
With CPC/NOAA pointing to a 98% chance of a very strong El Niño (index above +2.0°C) in the October-December 2026 quarter (CPC/NOAA, 10/08/2026), preparation before the event now carries as much weight as the data gathered after it.
This guide shows what technical analysis demands and where claims most often fall apart. If you already have a claim in preparation or filed, i4sea's free diagnostic points to the weakest layer of your report.
The first filter is contractual. In ANTT highway contracts, the typical wording leaves with the granting authority only cases of fortuitous event or force majeure that are not insurable in Brazil; one example clause requires that the event not have been insurable, in the previous year, by at least two insurers (ANTT vote, clause 20.2.3).
Before commissioning the report, check your contract's risk matrix, the insurance coverage available and in force, and the maintenance and resilience obligations for the affected asset.
The Evidence-Based Partial Rebalancing, created by IN 33/2024, applies when the right is uncontroversial or is in a condition for immediate recognition (art. 4, VII). ANTT advances an estimated amount, adjusted at the end of the main proceeding (art. 24, § 1), in cases of significant value and lengthy assessment (art. 24, § 2) (Agência iNFRA).
The partial award concerns the amount, not the merits. The first application, through Deliberação nº 206/2025, benefited CCR RioSP for emergency works on the BR-101/RJ/SP following the rains of March 31 and April 1, 2022 (SETCESP).
For you, the consequence is direct: the report must make the merits indisputable. A weak case does not lead to a smaller award; it sends the claim to the ordinary proceeding, with its own timeline.
A forecast is not proof. The analysis does not ask whether it was going to rain heavily, but whether it rained enough, in the stretch and at the time of the damage. A defensible report answers, in order:
The meteorological report must be signed by a meteorologist registered with CREA and holding an ART; the causal link is signed by a qualified engineer. Simple details can bring down reports: INMET publishes in UTC, and mixing time zones shifts rainfall and damage by three hours.
Under the sole paragraph of art. 393 of the Civil Code, force majeure requires that the effects of the event were impossible to avoid or prevent. In ANTT's practice, this means: if the concessionaire was alerted and had a forecasting tool available but did not take timely action, the damage ceases to be unforeseeable and is read instead as avoidable through omission.
Legal protection lies in documenting the management decision, not in accumulating alert bulletins. The source and time of the warning, who determined each action, exact times of preventive closure and reopening, mobilized teams, and field evidence with a date and time stamp. Before the Agency, a well-documented operational decision carries the same evidentiary weight as official rainfall data.
When CPC/NOAA points to a 98% chance of a very strong El Niño, the unforeseeable-event argument loses strength at the seasonal scale. The defense shifts to magnitude, inevitability and diligence.
The impact varies by region: above-average rainfall in the South and part of the Southeast, against a drier regime and greater fire risk in the North and Northeast (Jornal de Brasília, 10/02/2026). On highways, this means landslides and flooding on one side; smoke, fire in the right-of-way and pavement heat on the other.
In August, ANTT reinforced preventive action across concessions, focusing on drainage, slope containment, fire prevention and emergency response (SETCESP, 08/19/2026). And Portaria MT 622/2024 requires, for new projects, a minimum of 1% of gross revenue in resilient infrastructure (Agência iNFRA). Whatever a concessionaire prepares now is documented before the event.
i4sea delivers the layer most often missing from claims: proof that the operation saw the risk and acted in time. It does not replace the official data series nor sign off on the geotechnical causal link.
In parametric insurance, which pays out based on an objective climate index without case-by-case assessment, the central technical issue is basis risk: the index triggering without damage, or damage occurring without the index triggering. Measuring the index close to the asset reduces this mismatch.
The market is still small in the country and concentrated in agribusiness: it grew from 4 contracts in 2021 to 171 policies in 2024, with bottlenecks in climate data quality and index modeling (FGV Agro, Seguros Paramétricos no Brasil study, released in March 2026).
A claim already filed can still be strengthened. The work involves reconstructing documentation, not redoing the report: generally, the missing data already exists in a public source and simply has not been cross-referenced.
i4sea's diagnostic compares what was attached against the six questions above and points out the most common gaps: return period without comparison to the design, localized events without radar, times in different time zones, and operational action without documentation. You receive a list of what to reinforce, with no promise of a legal outcome.
Yes, if the effects were unavoidable with the reasonable measures available. That is why documenting the action taken after the alert carries as much weight as the meteorological data.
A meteorologist with active registration with CREA and an ART. The causal link between event and damage is signed by a qualified engineer, with their own ART.
On its own, hardly. It gains weight with installation conforming to technical standards, documented calibration, and validation against the official data series.
A comparison of the attached report against the six questions in this guide, a list of what to reinforce, and the sources where each piece of data can be found. There is no promise of a legal outcome.
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