Catastrophe models and risks

Catastrophe modeling helps insurers, reinsurers, financial institutions, corporations, and public agencies evaluate and manage natural and man-made catastrophe risk from perils ranging from earthquakes and hurricanes to floods and wildfires. With over 400 models in nearly 100 countries, you can assess and estimate the likelihood and severity of future disasters and their impact on your portfolio. 

Pine trees and scrub oak burn behind homes at the Wadsworth Ridge fire outside Denver Colorado on October 12, 2010. It is estimated to have burned 400 acres is in Jefferson County, near the Douglas County line close to Waterton Canyon and South Wadsworth Boulevard.
The cause is still under investigation. The location is behind a rifle firing range.


Catastrophe modeling framework

The basic framework for modeling the impacts of natural hazards on building inventories can be broken down into the following four modules:


Event module

Catastrophe modeling starts with the creation of a stochastic event set — a compilation of scenario events characterized by their strength, location, and probability of occurrence. This process involves simulating thousands of potential scenarios using realistic parameters and historical data to probabilistically forecast future events over time.

Hazard module

The hazard module assesses the level of physical hazard across a geographical area at risk. For example, a hurricane model calculates the strength of the winds around a storm, considering the region’s terrain and built environment.

Vulnerability module

The vulnerability module assesses the degree to which structures, their contents, and other insured properties are likely to be damaged by the hazard. It offers specific damage curves for different areas, accounting for local architectural styles and building codes.

Financial module

The financial module translates the expected physical damage into monetary loss. It takes the damage to a building and its contents and estimates who is responsible for paying. The results of that determination are then interpreted by the model user and applied to business decisions.


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Risk areas and types of models



Defining the industry's currency of risk

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10 of the top 10 reinsurance brokers choose Moody’s 

9 of the top 10 insurers of commercial lines choose Moody’s

9 of the top 10 insurers of commercial lines choose Moody’s

28 of the top 30 reinsurers choose Moody’s

28 of the top 30 reinsurers choose Moody’s


News and views

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2025 Catastrophe Review: Wildfires and severe convective storms dominate global losses
James Cosgrove summarizes Moody's RMS Event Response 2025 Catastrophe Review analyzing the main catastrophe events from last year, with insured losses dominated by wildfires in Los Angeles County, and severe convective storms in the U.S.
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Overcoming uncertainty, unlocking possibility: Introducing the Moody’s RMS™ North America Severe Convective Storm HD Models
Explore the key innovations that help the Moody’s RMS™ North America Severe Convective Storm (SCS) HD Models redefine the standard for SCS risk modeling, to deliver unprecedented accuracy and insight, all built on cutting-edge science and powered by Moody’s Intelligent Risk Platform.
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Live blog: Southern California wildfires

Keep updated with the latest information and insights from Moody's RMS Event Response and our wildfire experts.

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What is high-definition (HD) modeling?

High-definition models use advanced computing and data analytics for precise risk modeling, offering clarity and adaptability in insurance decision-making. They improve risk assessment accuracy through enhanced spatial coverage and granularity.

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2023 catastrophe review report

Against a backdrop of escalating natural disasters and increasingly interconnected risks, the 2023 catastrophe review report reveals a year marked by the rise of secondary perils.

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Mastering earnings risk: A study on physical risk in Europe and portfolio management

Moody’s comprehensive modeling solutions capture risk correlations across primary and secondary perils.

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Schrödinger’s cat model

Schrödinger’s cat concept applies to risk modeling, like flood defenses or fire risks, where outcomes are binary and unpredictable. Modelers must consider all scenarios for accurate risk assessments and effective disaster preparedness.

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How does an apartment fire turn into a catastrophe?

London’s Grenfell Tower fire highlights the catastrophic risk of flammable cladding on high-rises, underscoring the need for immediate action and reassessment of fire safety protocols and materials used in building exteriors.

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FAQs

Catastrophe models were originally developed to help the insurance industry underwrite rare but costly events. Today, industries beyond insurance are realizing the benefits of cat models. For example, catastrophe modeling allows land professionals to identify regions of potential risk and take proactive measures to mitigate their exposure. Government officials can use data from catastrophe models to set land-use policy in vulnerable regions. Lenders can also use catastrophe models to improve their lending practices, while surveyors include catastrophe modeling data in surveying reports.

Catastrophe models help you understand risk by translating hypothetical natural or man-made peril losses into real-world impacts on your portfolio. Modelers can understand catastrophe losses by analyzing a variety of loss metrics. Some of the key metrics include:

Exceedance probability (EP): EP is the probability that a loss will exceed a certain amount in a year. It is displayed as a curve to illustrate the probability of exceeding a range of losses, with the losses (often in millions) running along the X-axis and the exceedance probability running along the Y-axis.

Return period loss: Return periods are another way to express potential for loss and are the inverse of the exceedance probability, usually expressed in years (1% probability equals 100 years).  While this can be thought of as the average rate of exceedance over the long term, it is more accurate to say, “This loss has a 1 in 100 chance of being exceeded this year.”

Annual average loss (AAL): AAL is the average loss of all modeled events or periods, weighted by the probability of their occurrence. In an EP curve, AAL corresponds to the area underneath the curve, or the average expected losses that do not exceed the norm. Because of this, the AAL of two EP curves can be compared visually. AAL is additive, so it can be calculated based on a single damage curve, a group of damage curves, or the entire event set for a sub-peril or peril. It also provides a useful, normalized metric for comparing the risks of two or more perils even though peril hazards are quantified using different metrics.

Coefficient of variation (CV): The CV measures the size, or degree of variation, of each set of damage outcomes. Damage estimates with high variation, and therefore a high CV, will be more volatile than an estimate with a low CV. Mathematically, the CV is the ratio of the standard deviation of the losses (or the “breadth” of variation in a set of possible damage outcomes) over the mean (or average) of the possible losses.

Earnings risk in the insurance industry refers to the potential variability in profits due to factors such as claims payouts, investment returns, and operational expenses.

Catastrophe modeling plays a crucial role in assessing and managing earnings risk, particularly for property and casualty insurers. By simulating the potential impact of catastrophic events on insurance portfolios, catastrophe models help insurers estimate the likelihood and severity of future disasters.

By integrating catastrophe modeling into risk management practices, insurers can better quantify and manage their earnings risk associated with catastrophic events. This helps insurers better price policies, set aside sufficient reserves, and purchase reinsurance coverage to mitigate their exposure, thereby maintaining financial stability and resilience.

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Chartis RiskTech100 2026 Moody's Insurance award
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Chartis RiskTech AI50 2025 - Moody's AI-Driven Insurance Risk Analytics
Insurance ERM CRSA Awards 2025 winner Americas Economic scenario
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Insurance ERM CRSA Awards 2025 winner UK & Europe IFRS 17

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