Snowpack Layer Water Ratio Tool

Description

Sum layer thicknesses and thickness times snow/water density ratio; divide equivalent depth by snow depth or return zero with defined false.

Snow water equivalent expresses stored water as a depth using snow thickness and density. Layer accounting and liquid-water assumptions matter because separately included components can otherwise be counted twice.

Sum layer thicknesses and thickness times snow/water density ratio; divide equivalent depth by snow depth or return zero with defined false.

When to use this tool

Use Snowpack Layer Water Ratio when you need one supplied snow-storage or water-equivalent component.

How to use the tool and how it works

Enter layerThicknesses, snowDensities, waterDensity. Keep parallel arrays aligned. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read snowDepth, waterEquivalentDepth, equivalentRatio, defined. Inspect defined before interpreting the associated values.

Require aligned nonnegative layerThicknesses and snowDensities plus positive waterDensity. Sum layer thicknesses and thickness times snow/water density ratio; divide equivalent depth by snow depth or return zero with defined false.^[1]

Input field	Meaning and units	Accepted input
layerThicknesses	Layer Thicknesses	Required. Array of finite number; maximum items 256.
snowDensities	Snow Densities	Required. Array of finite number; maximum items 256.
waterDensity	Water Density	Required. Finite number; strictly above 0.

Output field	Interpretation	Returned shape
snowDepth	Snow Depth	Required. Finite number.
waterEquivalentDepth	Water Equivalent Depth	Required. Finite number.
equivalentRatio	Equivalent Ratio	Required. Finite number.
defined	Whether the associated ratio has its required denominator; inspect before using a zero placeholder.	Required. Boolean.

json

{
  "input": {
    "layerThicknesses": [
      1,
      2
    ],
    "snowDensities": [
      100,
      200
    ],
    "waterDensity": 1000
  },
  "output": {
    "snowDepth": 3,
    "waterEquivalentDepth": 0.5,
    "equivalentRatio": 0.16666666666666666,
    "defined": true
  }
}

Limitations and assumptions

Densities share units and depths share units; zero-depth ratio is a placeholder, with no compaction, melting, or layer-quality assessment.
Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.

Alternative or Complementary methods

Review the sampling method, density basis, layer structure, and complete snow-process model before estimating available water.

References

Calculation and input contract: hydrometeorology/snowpack-layer-water-ratio — tool.io

Similar or alternative tools

Snow Water Equivalent One Layer Term
Multiply nonnegative snowDepth by snowDensity/positive waterDensity for solidWaterEquivalent and add nonnegative liquidWaterDepth.
Snow Water Depth Contribution
Multiply nonnegative snowDepth by suppliedSnowDensity/positive suppliedWaterDensity for waterDepth, then by coveredFraction in [0, 1].