Avalanche Runout Alpha Angle Calculator
Compute observed release-to-runout alpha angle from physical measured horizontal distance/drop; not an avalanche prediction, GIS/geodesy transformation or safe runout exclusion zone.
Description
An observed avalanche alpha angle uses release-to-runout drop and horizontal distance.
An observed avalanche alpha angle uses release-to-runout drop and horizontal distance. It is a geometric descriptor of a recorded path.1
Enter finite elevations with release≥runout and positive horizontal distance. Return angle, allowing zero drop.
When to use Avalanche Runout Alpha Angle Calculator
Use Avalanche Runout Alpha Angle Calculator when you need to evaluate the supplied records under the calculation and evidence rules below. No predictive runout, GIS/geodesy transform or safe exclusion zone is determined.
Prepare the observed ice, snow, water or geometry measurements and explicit calibration parameters requested. Keep coordinates, datum, density and time units consistent.
How to use Avalanche Runout Alpha Angle Calculator and understand its results
- Prepare the observed ice, snow, water or geometry measurements and explicit calibration parameters requested. Keep coordinates, datum, density and time units consistent.
- Enter releaseElevationM, observedRunoutElevationM, horizontalRunoutDistanceM using the field table and calculation rules, then run the tool.
- Read observedRunoutAlphaDegrees. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| releaseElevationM | Release elevation m | number | Required |
| observedRunoutElevationM | Observed runout elevation m | number | Required |
| horizontalRunoutDistanceM | Horizontal runout distance m | number | Required |
Enter finite elevations with release≥runout and positive horizontal distance. Return angle, allowing zero drop.
angleDegrees=atan2(release−runout,horizontalDistance)×180/π Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| observedRunoutAlphaDegrees | Observed runout alpha degrees | number |
{
"input": {
"releaseElevationM": 1000,
"observedRunoutElevationM": 500,
"horizontalRunoutDistanceM": 1000
},
"output": {
"observedRunoutAlphaDegrees": 26.56505117707799
}
}Limitations and assumptions
No predictive runout, GIS/geodesy transform or safe exclusion zone is determined.
Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Ice Avalanche Volume Release Calculator: Detached-patch volume is an inventory calculation. A detached fraction describes supplied evidence rather than probability. For a complementary task, use Calving Front Cliff Height Above Water Calculator: Calving-cliff height can be measured relative to both water level and toe. A submerged top remains a signed observation.
References
-
Avalanche Runout Alpha Angle Calculator — tool.io
Similar or alternative tools
- Ice Avalanche Volume Release Calculator
Detached-patch volume is an inventory calculation. A detached fraction describes supplied evidence rather than probability.
- Calving Front Cliff Height Above Water Calculator
Calving-cliff height can be measured relative to both water level and toe. A submerged top remains a signed observation.