Introducing the PETS Avalanche Explosives Calculator
A New Tool to Help Avalanche Blasters Predict Effects, Improve Safety and Optimize Charge Placement
Avalanche hazard mitigation is a critical public safety activity in Colorado’s mountainous regions, where winter storms routinely deposit unstable snow layers across ski areas, transportation corridors, and public recreation zones. Each season, trained avalanche blasters enter steep, potentially unstable terrain to artificially trigger avalanches under controlled conditions before natural releases pose risks to the public. Although this work relies heavily on practitioner experience and local terrain
Knowledge of the physics governing how explosive charges interact with layered snowpacks is highly complex. Charge size, snow density, elevation, weak-layer characteristics, and terrain geometry all influence the effectiveness of explosive-triggered releases. Recognizing these challenges, Petr Explosives Group has developed a new predictive tool—the PETS Avalanche Explosives Calculator—designed to support blasters in making more informed decisions during avalanche mitigation missions. A key component of the calculator’s development is an ongoing collaboration with Sunlight Mountain Resort, located in Colorado’s White River National Forest, south of Glenwood Springs. The resort’s avalanche team brings extensive experience in operational mitigation, offering a real-world testing environment for tool validation.
Through this collaboration, PETS and Sunlight Mountain Resort are jointly engaged in validating the calculator’s modeled predictions, collecting field data during mitigation missions, refining weak-layer pressure thresholds, evaluating charge placement strategies, and developing hands-on training tools for both new and experienced blasters. It also creates a high-value teaching platform where blasters can explore “cause-and-effect” relationships that are difficult to visualize in the field. From new patrollers in training to veteran blasters refining their methods, this joint project is raising the bar for avalanche education.
Understanding the Challenge: Explosives used in avalanche work function by sending a shock wave into the snowpack. If that wave delivers enough pressure at the depth of a critical weak layer, the layer collapses and the slope releases. But that pressure depends on an intricate mix of variables:
• Charge size
• Explosive type and TNT equivalence
• Snow density and aDenuaEon
• Weak-layer depth
• Slope angle
• Air temperature and elevation
• Placement on the surface or suspended above it
These aren’t theoreScal concerns—they’re everyday decisions blasters make on ridgelines, often in high winds, blowing snow, and limited visibility. Field experience remains invaluable, but expertise combined with a predictive tool creates a stronger foundation for decision-making.
The PETS Avalanche Calculator: Turning Complexity into Clear Answers. The PETS Avalanche Explosives Calculator allows blasters to enter the conditions of the day—charge weight, snowpack profile, slope angle, and weak-layer depth—and immediately see a modeled prediction of the pressure delivered to the weak layer. Its adaptability makes it especially powerful for both planning and training.
For more information, please get in touch with Dr. Petr at Petr Explosives Group.
