Prescribed fires are a necessary process for rangeland management, helping to reduce fuel loads, restore ecosystems, and mitigate the risk of catastrophic wildfires. More importantly, the estimated escape rate across the U.S. is quite low, at 0.16% (2022). A recent study by Li et al. (2025) sheds light on the spatial and temporal patterns of escape prescribed fires, offering crucial insights for rangeland managers and fire professionals.
Let’s break down what makes a prescribed fire more likely to “escape” and what we can do to minimize that risk.
The timing of prescribed fires are crucial. This study found that:
- Prescribed fires are most frequent in October, with spring being the second most frequent burn window. This aligns with many fire management strategies that leverage cooler, potentially wetter conditions, with peak biomass for burning.
- However, most escapes occur in May, and are most likely in July and August.
- The risk of escape is highest just before the summer wildfire season.
- The good news? The estimated escape rate across the US is quite low, at 0.16% (2022). While every escape is a concern, this low percentage reflects the overall diligent planning and execution involved in prescribed fire operations.
Key takeaway for rangeland managers: Take advantage of fall burn windows to minimize wildfire escape probability. This period often offers more stable atmospheric conditions and higher fuel moisture, making prescribed fire escapes less volatile. .
Environmental Factors: What Else Plays a Role?
Perfect Storm: humidity, temperature, and wind: Despite vegetative density, the confluence of extremely high temperatures and wind speeds, as well as low humidity levels and precipitation, increases the risk of prescribed fire escapes.
Beyond timing, environmental conditions are major contributors to prescribed fire bonus acres.
Wind: A Fickle Friend (or Foe)
It’s no surprise that wind is a significant factor:
- Higher winds are associated with an increased risk for prescribed fire escape. Specifically, speeds of 10 meters per second (approximately 22 mph) or greater significantly increase the risk.
- Erratic wind speed and direction make it more challenging to predict fire behavior. This unpredictability can quickly enhance probabilities of ignition.
Vegetation Type: Fueling the Fire
The type of vegetation targeted can also influences escape risk:
- TREES are the DOMINANT cover in areas of escaped fires, accounting for ~20-60%. This makes sense, as tree canopies can carry fire more easily, especially with higher winds.
- Herbaceous cover (grasses, forbs) is the second most frequent vegetation type, at ~40-50%. While herbaceous fuels can burn quickly, their fire behavior is often more predictable than that in forested areas, assuming similar conditions.
The Bottom Line
Understanding these common temporal and environmental patterns is crucial for improving the safety and effectiveness of prescribed fire programs. By paying close attention to burn windows, weather forecasts (especially wind), and the types of vegetation in a burn unit, fire managers can further reduce the already low risk of escaped prescribed fires. This research provides valuable data to support adaptive management strategies and ensure that prescribed fire remains a powerful tool for healthy landscapes.
For the full study, be sure to read more Temporal and spatial pattern analysis of escaped…