Understanding Post-Wildfire Hazards & Insurance Implications: A Conversation with Leading Geomorphologist John Norman

As wildfires like the recent ones in Los Angeles become increasingly prevalent across our landscapes, understanding their long-term impacts becomes crucial for land managers and insurance providers alike. We sat down with Teren’s John Norman, a geomorphologist with over two decades of experience studying post-wildfire landscapes, to discuss the critical risks and considerations facing professionals in this field.

On Debris Flow Hazards

Q: John, what’s the most misunderstood aspect of post-wildfire debris flows?

What many people don’t realize is that debris flows after wildfires are fundamentally different from typical landslides. We’re dealing with a completely altered landscape where even gentle slopes can become hazardous. The fire doesn’t just burn vegetation – it fundamentally changes the soil structure itself.

Q: How does this impact risk assessment for land managers and insurers?

Traditional risk models often fall short in post-wildfire scenarios. When I’m in the field, I’m looking at factors that wouldn’t typically enter into standard geological assessments. The burn severity patterns, the soil’s new hydrophobic properties, the changed infiltration rates – these all create a new paradigm for risk.

Watershed Impacts: A Complex Web

Q: You’ve spent considerable time studying watershed impacts. What should professionals be most concerned about?

Water quality changes after a fire are immediate and can be severe. But what keeps me up at night is the long-term cascade of effects we see in watersheds. We’re not just talking about increased sediment loads – though those are significant. We’re seeing fundamental changes in how these systems process and transport water, nutrients, and contaminants.

Q: Can you elaborate on these long-term effects?

Think of a watershed as a living system. When a fire moves through, it doesn’t just affect the surface. We see changes in groundwater recharge patterns, altered peak flows, and modified channel morphology. These changes can persist for decades, and they’re often overlooked in initial assessments.

Insurance Industry Implications

Q: Let’s talk about insurance provision in high-risk areas. What factors should providers consider when assessing wildfire risk?

The key is understanding that wildfire risk assessment isn’t just about the wilderness-urban interface anymore. Insurance providers need to look at three distinct zones of analysis: the individual property level, the community scale, and the broader landscape context.

Q: Can you break down what providers should look for in each zone?

At the property level, it’s all about the home ignition zone. We’re looking at the immediate 0-5 feet around structures, then the intermediate zone from 5-30 feet, and the extended zone out to 100 feet. Insurance providers can significantly reduce their exposure by evaluating specific defensible space criteria within each of these zones.

Q: What specific elements should they evaluate?

It’s a comprehensive assessment. In the immediate zone, we’re looking at things like ember-resistant venting, fire-resistant roofing materials, and cleared gutters. In the intermediate zone, proper spacing between vegetation becomes crucial. And in the extended zone, we’re evaluating the transition between maintained landscapes and wildland fuels.

Q: How does this relate to the broader landscape assessment?

This is where the science of fuel modeling becomes critical. Insurance providers need to understand the relationship between ground and canopy fuels in the surrounding landscape. We’re looking at factors like vertical fuel continuity from ground to crown, horizontal fuel continuity across the landscape, seasonal changes in fuel moisture content, and local topography and wind patterns.

When providers understand these relationships, they can make much more informed decisions about risk exposure.

Q: How can insurance providers use this information to maintain coverage in high-risk areas?

It’s about moving from binary risk assessment to a more nuanced approach. By understanding both defensible space and fuel dynamics, providers can create tiered risk categories. Properties that meet specific mitigation criteria in high-risk areas might actually present lower overall risk than poorly maintained properties in supposedly ‘safer’ areas.

Q: Any specific recommendations for providers looking to refine their risk assessment?

I recommend developing a scoring system that weighs both controllable and uncontrollable factors. Controllable factors could include defensible space maintenance, building material choices, emergency access considerations, community-level fire protection resources, while uncontrollable factors could include regional fire history, climate trends, topographical features, and seasonal weather patterns. Teren’s Wildfire Data Suite scores parcels by adhering to defensible space standards, such as Firewise USA, and performs parcel-to-parcel comparisons within neighborhoods.

Climate Change and Future Risks

Q: How is climate change affecting post-wildfire recovery patterns?

What we’re seeing now is unprecedented. The combination of more intense fires and changing precipitation patterns is creating recovery scenarios we haven’t historically had to deal with. Land managers and insurers need to be prepared for these new patterns.

Q: What’s your key message for professionals working in this field?

Collaboration is crucial. Land managers and insurance providers need to think outside of the box and forge partnerships across community organizations, data intelligence providers, and beyond. work together more closely than ever. The good news is, we’re already seeing this happening with policy being pushed forward on State and Federal levels, as well as with projects like the Hermit’s Peak Wildfire Response.

Looking Forward

Q: Any final thoughts on the future of post-wildfire risk management?

We’re in a critical period of learning and adaptation. The good news is that our understanding of these systems is growing rapidly. The challenge is implementing this knowledge effectively. Success will depend on our ability to bridge the gap between scientific understanding and practical risk management.

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John Norman continues his research on post-wildfire landscapes while consulting on projects for government agencies like the NRCS and USFS, as well as insurance providers. His work has formed the building blocks of Teren’s Wildfire Data Suite and Land and Forestry work.