Innovative Avalanche Marking Device

The Challenge

Companion Rescue Efficiency Has Plateaued i

While avalanche safety technology has advanced, companion rescue times still vary widely and remain constrained by real-world conditions and human factors. Swiss avalanche records indicate that median companion rescue time (burial to extrication) has been ~10 minutes since the 1990s, with the interquartile range across 1981–2020 measuring ~5–20 minutes—meaning roughly one in four rescues takes longer than ~20 minutes. Despite advances in equipment, this highlights the value of reducing uncertainty during localisation and pinpointing.

Select Metric

Companion Rescue (Median & IQR)

Number of Burials

Survival Probability

The Solution

Visual Marking
Rapid Localisation

AvaBuoy is a lightweight, mechanical device designed to complement existing avalanche safety gear by providing a visual surface marker and physical connection in avalanche scenarios.

Visual Surface Marker Low-density 5 L marker designed to decouple from the user and rise towards the surface through granular segregation (dry) and buoyant ascent (wet)—helping establish a high-contrast surface reference as the avalanche comes to rest.
High-Strength Cord A 5 m steel-cored, Dyneema-sheathed cord provides a physical connection between the surface marker and the user, designed to support more efficient localisation and coordination during companion rescue.
Safety Add-On Engineered to complement transceivers, probes, and shovels for high-alpine environments. Intended to enhance the standard safety kit where visual cues are often lost in vast debris fields.
Compact & Lightweight Weighing just 300g (total system weight), it adds an additional layer of capability without the weight penalty - making advanced visual marking accessible to every backcountry enthusiast.

How It Works

From Deployment to Rescue

Designed to integrate with standard avalanche safety procedures.

Step 1

System Deployment

During an avalanche, the release mechanism is designed to inflate and deploy the buoy from the thigh-mounted holster. Once separated, the buoy moves independently within the debris flow.

Step 2

Visual Identification

Once the avalanche comes to rest, the high-contrast surface marker serves as an immediate visual reference—enabling rescuers to orient, coordinate, and focus the search area.

Step 3

Physical Reference Line

A 5 m steel-cored, Dyneema-sheathed cord provides a physical reference line from the surface marker towards the buried victim. Under tension, it is designed to resist abrasion and track through surface layers and debris—supporting a faster transition from localisation to pinpointing, while transceivers remain active to validate the search area.

Step 4

Narrow the Pinpoint Area

The cord’s exit angle provides the cue: it emerges shallow when the lateral offset is larger and steepens as that offset shrinks. When it hangs close to vertical, horizontal separation is minimal—further narrowing the pinpoint area to the most likely burial location, ready for confirmation (and with a fixed 5 m cord, if ~4 m of cord is visible/on the surface, ~1 m of cord length remains buried).

Step 5

Confirm & Excavate

With the pinpoint area focused on a single location, transceiver confirmation serves as a final cross-check and probing establishes depth before excavation begins. AvaBuoy is designed to reduce uncertainty up to this point—excavation speed depends mainly on depth, debris density, team size, and technique.

The Impact

Completing Your Safety System

Companion rescue times vary widely—and in avalanche burial scenarios, minutes often decide outcomes. Transceivers are essential, but time is often lost to uncertainty: pinpointing the exact location and transitioning efficiently into excavation under stress. AvaBuoy is designed to add redundancy through a rapid visual and physical reference alongside transceiver signals, helping rescuers move faster from “searching” to “excavating,” especially under stress or with less experience.

Rescue Workflow Comparison CRITICAL BURIAL SCENARIOS

Standard Kit

Observed Rescue Time (IQR): ~5–20 min (varies)Observed (IQR): ~5–20 min i

Signal Search Signal

Pinpointing Pinpoint

Excavation

Standard Kit + AvaBuoy + AvaBuoy

Target Time Saved: ~2–8 min (theoretical)Target Saved: ~2–8 mini

Visual

Accelerated Pinpointing Accelerated

Excavation

In multi-burial scenarios where transceiver signals can overlap, a visual marker can serve as a rapid reference point for triage and coordination, while transceivers remain essential to isolate and confirm each burial location. All targets shown are theoretical until independent field validation.

The System

Swiss-Engineered Components

Key elements designed for reliability in extreme conditions.

Activation

Mechanical trigger rapidly inflates the buoy (< 2s) via a sealed gas canister. Engineered for extreme cold reliability, eliminating battery dependence for the critical inflation.

Orange Buoy

Low-density 5 L marker constructed from high-tenacity nylon. Features an auto-activating LED strobe to maximise visibility in low-light and poor-contrast conditions.

Reinforced Cord i

Flexible 5 m steel-cored, Dyneema-sheathed cord designed for abrasion resistance and debris tracking. Features a Two-Stage Protection System combining a rip-stitch with a calibrated trauma fuse.

Holster

Optimised thigh-mount system positioned near the body’s centre of mass for stability and intuitive access. Designed to preserve freedom of movement during technical ascents and descents.

The Science

Avalanche Dynamics

Avalanche debris segregation depends strongly on moisture and cohesion. Dry, cohesionless granular flow promotes size-driven sorting through kinetic sieving and squeeze expulsion. As liquid content and cohesion increase, void percolation weakens and density effects become relatively more important, favoring low-density objects nearer the surface as the debris decelerates and settles.

Mechanism 01

Kinetic Sievingi

In dry, low-cohesion avalanches, the dense core can behave as a cohesionless granular flow. As the mass moves and agitates, shearing forces create temporary voids between snow grains. Smaller particles preferentially enter these gaps and sift downwards (kinetic sieving), while larger objects that exceed the size of these voids are displaced upward by squeeze expulsion—the classic “Brazil nut effect.” This natural sorting process results in a net upward drift of larger objects relative to the bulk of the moving debris.

Mechanism 02

Cohesion & Densityi

In wet debris flows, snow can behave like a dense, cohesive slurry. Added liquid and cohesion dampen the relative motion that drives dry kinetic sieving, so percolation-based size sorting weakens. When percolation is suppressed, density contrast becomes more influential: low-density objects experience buoyancy-like lift and reduced downward motion, and tend to drift upward relative to denser material during shear in the moving debris.

Mechanism 03

Physical Decoupling

A person is typically much denser than avalanche snow and is therefore often carried lower in the flow, ending up deeper in the debris. Decoupling allows the buoy to move and segregate as an independent object within the moving debris, exposing it to the same sorting processes described above in both dry and wet flow regimes, while the cord maintains a physical link to the buried person.

Launch Simulator

The Segregation Thresholdi

In dry debris flows, size-driven segregation (kinetic sieving) is often stronger, while in wet, cohesive debris flows, percolation weakens and density effects become more important. Use this chart to switch between avalanche types and see where objects sit relative to the simplified threshold.

Avalanche Type

Dry Soft Slab (250 kg/m³)

Dry Low-Density (150 kg/m³)

Dry Soft Slab (250 kg/m³)

Dry Hard Slab (350 kg/m³)

Wet Dense Debris (550 kg/m³)

Compare Objects

Density Ratio, R_d = ρ_o / ρ_s

Size Ratio, R_s = d / d_ref

Upward Segregation

Size-driven segregation is treated as more influential: objects larger than the grains (R_s > 1) tend to rise towards the surface relative to the moving debris grains, particularly when R_d is not too high."

Downward Segregation

Density contrast is treated as more influential: higher R_d objects tend to sink relative to the moving debris grains, and very small objects (near grain scale, R_s ≈ 1) are less likely to gain net upward drift.

Be Seen Be Found Faster

Companion Rescue Efficiency Has Plateaued i

Visual Marking
Rapid Localisation