SnowVisorNew snow measures an interval
A snowfall report needs a time window to be useful. Overnight snowfall, a 24-hour total and a storm total can all be correct while showing different numbers. Check the end time as well as the amount.
The National Weather Service distinguishes newly fallen snow from total snow depth. Its observing guidance also explains why consistent timing and a representative measurement site matter.
The base is a changing snowpack
Snow already on the ground can settle, melt or be redistributed by wind while more snow is falling. A resort may also report a base measurement from a different elevation or location than another source. That makes a simple subtraction between two reports unreliable.
For example, a report of 20 cm of new snow alongside a base that rose by only 10 cm is not automatically an error. First compare the timing, location and measurement definitions. Do not assume either number describes every run on the mountain.
Water equivalent is a third measurement
Snow water equivalent describes the amount of water represented by the snow. It is a different quantity from snow depth, so a value in millimetres of water should not be compared directly with centimetres of snow.
There is no single conversion that describes every snowfall. Check the label and units rather than applying a familiar ratio to all conditions.
Use the number that answers your question
If you want to know whether snow arrived last night, look for the recent snowfall total and timestamp. If you want context for the existing cover, look at the reported base and where it was measured. If you want to plan ahead, read forecast snowfall separately from both observed values.
- Compare like time windows: 24 hours with 24 hours.
- Compare like locations and elevations where they are provided.
- Keep measured totals separate from forecast totals.
- Use current resort reports and imagery to add context.
Read SnowVisor’s labels before comparing
The resort page brings several kinds of mountain information together. Read the label beside each value and check whether a provider has supplied current data. A missing measurement is different from a measured zero; neither should be silently filled with an optimistic estimate.