Snowfall Accumulation Calculator
Project total snow depth from the snowfall rate, duration and settling.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
This scenario multiplies a constant entered snowfall rate by storm duration, then applies your chosen settling percentage and adds existing snow. Snowfall rate, compaction and water-to-snow ratio vary over time and by storm, so this is not a forecast.
Worked example
calculated with the default values below
Snowfall rate 1 in/hr · Duration of the storm 6 hours · Settling and compaction 15 % · Snow already on the ground 0 in · Temperature 25 °F Total snow that falls 6.0 in · Settled depth on the ground 5.1 in · Depth including what was already there 5.1 in · Settled depth 13.0 cm · Water equivalent 0.60 in · Storm category Heavy
General background references
Disclaimer
These calculators give general estimates. Sizing, pricing, availability and standards vary by brand, retailer and country, so treat the output as a starting point and confirm it against the seller's or authority's own figures.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
F = r×h; D = F×(1 − s÷100) + e; W_eq = F÷R(T); cm = 2.54D
- r
- Snowfall rate (in/h)
- h
- Duration (h)
- s
- Settling loss (%)
- e
- Existing depth (in)
- T
- Temperature (°F)
- D
- Final depth (in)
- F
- Fresh snowfall (in)
- R
- Snow-to-water ratio by temperature (see note)
- W_eq
- Water equivalent (in)
- cm
- Final depth (cm)
Fallen snow = rate × duration; settled depth = fallen snow × (1 − entered settling fraction) + existing depth. Water equivalent uses a coarse temperature band, not a forecast.
Frequently asked questions
Is the result a snowfall forecast?
No. It assumes a constant snowfall rate and user-selected settling percentage. The temperature-based water-to-snow ratio is a rough band, and real rates and compaction change during a storm.