Climate Risks on Highways: How to Anticipate Closures

Climate risks on highways combine heavy rain, fog, landslides and flooding with the layout and condition of each road segment. Together, they determine the likelihood of closure within a window of hours or days. Unlike the isolated disaster reported after the fact, this risk follows an identifiable pattern. Mapped in advance, it allows route, timing and contingency decisions before cargo gets stranded on the road.

• Climate risks on highways account for R$485 billion in losses over the past 11 years in Brazil, according to a survey cited by Estadão in partnership with WayCarbon.
• Rain, fog and landslides are responsible for most closures recorded on federal and state highways.
• Brazil's transport regulator ANTT already requires contingency plans and operational risk management from highway concessionaires, making climate anticipation part of the sector's compliance.
• High-resolution models (1 to 3 km) capture the local risk pattern of each road segment, unlike the generic forecasts most carriers rely on today.
• Anticipating a closure days in advance reduces the cost of idle fleets, lost cargo and contractual penalties for delayed delivery.

Every highway exposed to rain, fog or landslides has a predictable risk calendar. The closure that catches a carrier off guard actually follows a pattern of conditions repeated year after year, segment by segment. The problem is not a lack of weather data. It is the lack of data calibrated for that specific kilometer, not for the nearest city.

Operational climate risk is the probability that a specific weather condition (rainfall above a certain volume, fog with reduced visibility, slope instability) will compromise the safe operation of an asset at a defined point and period. On highways, it means knowing that the volume, duration and geotechnical history of that kilometer make a preventive closure likely within the next 48 to 72 hours.

This is the distinction that separates risk management from disaster response. And it is the distinction that almost no carrier or logistics operator can make today, because public forecasts were not designed to answer this question.

What climate risks on highways actually are

Climate risks on highways describe the probability that a weather event (rain, fog, wind or slope instability) will compromise the passability of a specific segment, with direct impact on safety, delivery time and logistics cost. The definition is not academic: it comes from cross-referencing measured atmospheric conditions with the closure history of that point in the network.

The difference between "it will rain" and "the segment will close" lies in the geotechnical and operational history of each kilometer. An unstable rock cut in a mountain pass reacts to 80 mm of accumulated rainfall. A flat segment with poor drainage reacts to 40 mm in a few hours. The same rain, at different points of the same highway, produces opposite outcomes.

Research linked to Made/USP (Mobilidade Amanhã) already treats transport infrastructure and climate as a risk engineering problem, not generic meteorology. What matters is the physical vulnerability of the asset combined with the frequency of the event threatening it.

At i4sea, this logic guides monitoring: each segment carries its own closure threshold, built from its own history rather than a single rule applied to the entire network.

How much Brazil loses to climate disasters on highways

Brazil lost R$485 billion over 11 years to climate disasters directly affecting road infrastructure, according to a survey by Estadão in partnership with WayCarbon. The figure covers recovery works, logistics disruption and cargo loss, placing highways at the center of the country's losses from extreme events.

This number is not isolated. A Susep report released in September 2026 found that only 9% of economic losses from climate disasters in Brazil are covered by insurance, against 45% globally. Aon calculated US$5.4 billion in climate disasters in 2025 alone, according to Folha de S.Paulo (Feb/2026).

Cemaden recorded roughly R$2.9 billion in damages in the same year.

Reading these numbers together shows a trend, not an isolated event: the cost grows year after year, and most of it falls on those without insurance coverage. For carriers and concessionaires, the cost of a closure does not show up only in contractual penalties.

It shows up in idle fleets, detour fuel, lost cargo and insurance that, in 9 out of 10 cases, does not cover the event.

Which weather hazards close highways most often in Brazil

Heavy rain, fog and slope landslides account for most closures recorded on Brazilian federal and state highways. Each hazard has its own signature: rain closes roads through flooding or by triggering preventive landslide protocols, fog closes roads due to reduced visibility, and landslides close roads by physically blocking the lane or threatening slope integrity.

AdaptaBrasil, a platform run by Brazil's Ministry of Science, Technology and Innovation (MCTI), already provides climate exposure data applied to the federal highway network, cross-referencing extreme rainfall projections with road layout.

The data confirms what operations already experience: mountain segments concentrate landslides, coastal segments concentrate flooding and fog, and highways in the Center-West and Northeast concentrate short-duration convective rain that is hard to predict in advance.

In February 2026, Agência Brasil reported flooding and closures on BR-116 and BR-495 in Rio de Janeiro, affecting public transport and municipal services. That same month, the concessionaire operating the Rio-Santos highway (BR-101) announced monitoring of 27 critical points and preventive closure whenever accumulated rainfall exceeds 100 mm, according to G1.

The pattern repeats: the point is known, and the decision relies on a rainfall threshold.

Why generic forecasts fail to predict closures on your route

Generic forecasts fail to predict closures because they work at a coarse resolution, typically 25 km, while closure risk originates in a segment just a few meters long. A forecast of "moderate rain for the region" can hide a concentrated convective cell sitting exactly over the mountain cut that historically closes with less rainfall.

In operational practice, this shows up as the mismatch between a bulletin saying "clear weather" and a concessionaire declaring a preventive closure that same day. It is not a forecasting error: it is a scale error. The 1 to 3 km resolution used by i4sea distinguishes rain behavior cell by cell, which changes the decision of when to release or hold a convoy.

This explains why searches like "Dutra highway closure," "Imigrantes highway closure" or "Régis Bittencourt highway closure" spike every rainy season. The information exists, but it arrives late, usually after the concessionaire has already closed the segment. The goal of calibrated monitoring is to reverse that order: deliver the probability of closure before the official decree, not as confirmation of it.

The risk calendar: predicting closures before cargo reaches the road

The risk calendar is the time-based representation of a segment's closure probability, built by cross-referencing that point's closure history with high-resolution weather forecasting. Instead of a binary answer ("will it close or not"), it delivers the probability of restriction by time window, days in advance.

The methodology starts with multifactor analysis: for each monitored segment, accumulated rainfall, hourly intensity, soil moisture, geotechnical history (where applicable) and the concessionaire's own record of previous closures are cross-referenced. The result is a pattern specific to each highway, not a generic threshold applied to the whole network.

In practice, this calendar delivers three pieces of information to logistics operations: the highest-risk window over the next 24 to 72 hours, the specific segment most exposed within the planned route, and a recommended adjustment (move up departure, delay it, or reroute). The decision happens before the closure, not as a reaction to a "road closed" sign.

ANTT and climate compliance: what is already required of concessionaires

Brazil's transport regulator ANTT already requires contingency plans and operational risk management from highway concessionaires, and climate risk carries growing weight in that compliance. In August 2026, the agency stepped up inspection and resilience measures on highways facing a strong El Niño, with a model that targets oversight based on each concession's performance and specific conditions.

This shift reflects a broader movement by Brazilian regulators: treating climate risk as an auditable operational management variable, not a generic force majeure claimed after the fact. The repeal of CVM Resolution 218 by CVM 244 in 2026 does not remove this pressure: institutional investors continue to push for voluntary climate risk disclosure in line with IFRS S2, including from infrastructure concessionaires.

For the concessionaire or carrier that depends on a concessioned highway, having a documented history of monitoring, alerting and decision-making has stopped being a differentiator and become part of the compliance file. When a closure happens anyway, the record showing the condition was monitored and communicated in advance supports the contractual defense with shippers and regulators.

To structure this process, see the climate contingency plan guide.

Landslides and flooding: the two risks that most often stop highways

Landslides and flooding close roads in different ways and require different monitoring: a landslide is a geotechnical instability risk that accumulates over days of rain, while flooding is a drainage risk that can form within a few hours of heavy rain. Treating both with the same alert threshold is the most common mistake among concessionaires still using generic forecasts.

Landslides respond to accumulated volume and soil saturation, which is why protocols like the Rio-Santos highway's use a 100 mm trigger for preventive closure. Flooding, on the other hand, responds to hourly rainfall intensity and local drainage, which explains why urban segments like BR-116 and BR-495 close after shorter events.

More details in the article on landslides on highways.

Frequently asked questions

References