Utility Wildfire Investigations: Why the Failed Component Is Only the Beginning

A utility wildfire investigation must do more than identify the electrical component associated with ignition. It must explain why the failure occurred, how multiple factors contributed, and which findings matter most for evaluating risk, determining the root cause, and guiding future mitigation efforts.

Every wildfire has an origin and cause. Origin and cause investigations are essential, but they rarely explain the full story. Understanding why and how an electrical failure became a wildfire requires looking beyond the failed component or the area of origin.

Origin identifies where a fire started. Cause identifies what initiated it. Root cause analysis goes further by explaining the underlying reason (or reasons) why a failure occurred, and how the circumstances contributed to ignition and propagation of the wildfire.

A failed conductor, a tree fallen on a power line, or other potential electrical ignition source may lead to the initial spark, but the wildfire itself is usually the product of multiple conditions converging at the same time. Understanding how and why those conditions contributed to the utility wildfire is what investigators seek to understand in a root cause investigation. These findings can then be turned into lessons for future mitigation efforts.

Why Similar Electrical Failures Can Produce Different Outcomes 

Why does one utility equipment failure become a catastrophic wildfire while another remains a small, contained fire?

Utility-associated wildfires represent a relatively small percentage of wildfire ignitions, yet they often result in disproportionately severe losses. One explanation for this is that utility equipment failures are most likely to occur during the same conditions that cause fires to spread rapidly: high winds.

The conditions surrounding the failure often influence the outcome. When electrical equipment fails during severe fire weather, the failure can quickly develop into a catastrophic wildfire before suppression is possible.

Consider two similar overhead conductor failures, Failure A and Failure B. In Failure A, the conductor falls near a road during cool, calm weather. The surrounding vegetation is sparse and still damp from recent rainfall. Protective devices operate as intended and de-energize the line quickly. Under those conditions, the resulting fire may remain small and contained.

Now consider Failure B, the same as Failure A except for a few differences: it occurs during high winds, and nearby vegetation is dry and overgrown. The terrain allows fire to spread rapidly uphill, and the line remains energized even briefly. What begins as a comparable equipment failure can escalate into a major wildfire because the surrounding environmental conditions are far less forgiving.

Evaluating the combination of these factors reveals more than only examining the wildfire's origin and cause. It helps organizations focus their attention on contributing risks.

What Evidence Do Utility Wildfire Investigators Examine?

To understand why a utility wildfire occurred, investigators examine the entire sequence of events that led to ignition, often looking back several years before the incident. Their analysis may include:

• Physical evidence from the fire scene 
• Weather conditions 
• Vegetation information 
• Electrical infrastructure configuration 
• Maintenance records 
• Real-time electrical data 
• Communications records 

Together, these sources help investigators determine not only how the wildfire started, but why it developed the way it did.

What Utility Wildfire Investigations Teach Us About Managing Wildfire Risk 

Utilities already understand the available wildfire mitigation strategies. The challenge is determining how to meaningfully prioritize these efforts to reduce risk. This is where forensic investigations provide lasting value.

Utilities may prioritize strategies such as: 

• Conductor upgrades 
• Vegetation management 
• Enhanced inspections 
• Undergrounding conductors
• Fault detection technologies 
• Reclosing protocols
• Public Safety Power Shutoffs (PSPS) 

Each strategy has value, but no utility can implement every strategy everywhere at once. Undergrounding power lines, for example, can significantly reduce wildfire risk in some locations, but it is also one of the most expensive infrastructure investments a utility can make. Utilities must balance infrastructure upgrades with other necessary repairs, maintenance, and expansion efforts while prioritizing system reliability and affordability.

Each utility wildfire investigation generates more data points. Over time, patterns emerge. Investigators see which failure mechanisms appear repeatedly, how environmental conditions influence outcomes, and where multiple factors consistently coincide to present the greatest risk. Those patterns help organizations distinguish between theoretical risks and the failure mechanisms that consistently contribute to catastrophic losses.

Applying Utility Wildfire Investigation Findings to Future Risk 

Each utility wildfire investigation aims to answer the immediate question about origin and cause, but the most thorough investigations will turn one event into insight that extends well beyond a single event.

Those findings provide context for understanding how design decisions, maintenance practices, and operational conditions can contribute to wildfire risk. As wildfire activity increases across the country and electrical infrastructure continues to age, those insights become increasingly valuable for prioritizing future investments and improving system resilience.

While forensic investigations cannot eliminate wildfire risk, they can provide evidence-based insight into how electrical systems actually fail and which mitigation measures deserve the greatest attention moving forward.

Finding the failed component is only the beginning. The greatest value of a forensic investigation comes from understanding why and how the failure led to the wildfire and then applying those lessons to future risk.

Need Help Evaluating Utility Wildfire Risk? Our Forensic Team Can Help Investigate and Assess Electrical System Risk