Read the snow numbers
Snow depth vs snowfall: which number helps plan your ski day?
Understand new snowfall, existing snow depth and snow water equivalent. Compare the right numbers before choosing a mountain with your ski or snowboard friends.
By SkiBuds · Updated
A mountain can report a deep base while expecting little new snow. A storm can deliver new snowfall while the settled snow depth rises by less. Before your group compares mountains, agree on the question: are you looking for fresh snow, existing coverage, or the water stored in the snowpack?
Three measurements, three questions
| Number | What it describes | How to use it |
|---|---|---|
| New snowfall | Snow that falls over a stated period | Compare the same period and distinguish a forecast from an observed report. |
| Snow depth | Snow already on the ground at a measurement point | Check where and when it was measured before treating it as mountain-wide coverage. |
| Snow water equivalent (SWE) | The liquid-water depth represented by the snowpack | Read it as water content; it is not the same number as snow depth or fresh snowfall. |
The NRCS interactive-map glossary defines snow depth as the distance from the snow surface to the ground, and SWE as the water represented by the snowpack. Its station measurements describe a location and observation time.
Why yesterday's snowfall may differ from today's depth change
Snow settles and melts, and wind can redistribute it. Adding yesterday's reported snowfall to an older depth reading will not necessarily reproduce today's depth. The NWS snow measurement guidelines distinguish accumulated new snowfall from the snow remaining on the ground and explain the effect of settling and melting.
For example, hypothetical reports of 8 inches of new snow and a 4-inch increase in settled depth are not automatically contradictory. Verify the observation periods and locations before deciding that one report is wrong.
Compare the same mountain location and time window
- Open the resort forecast and note its source, location and update time.
- Check whether the snow figure is predicted or measured. A forecast is an estimate of future snowfall, not a completed observation.
- Read the period: overnight, 24 hours and a storm total answer different questions.
- If using a nearby snow station, check its location and elevation. A station reading is evidence about that station, not every run at the resort.
- Confirm terrain and lift openings with the operator. Snow totals alone do not establish which runs will open.
Send your friends the numbers with their labels
Instead of “the mountain has 12 inches,” send a message like this:
For our Saturday plan, let's compare the overnight snowfall forecast with the resort's morning report. We'll recheck the update time, wind and road information before leaving. Meet at the agreed base-area point, and confirm the return plan tonight.
This is a planning example, not a current forecast. Use the snow forecast guide, powder-day group plan and meetup checklist to turn the weather check into an agreed day together.
Go deeper with the original sources
- NRCS snow and water interactive map: measured snow depth and SWE layers.
- NWS probabilistic winter forecasts: snowfall outlooks and their uncertainty.
- Official weather, road and avalanche resources: separate checks for different parts of your trip.