By Sam Collentine, Meteorologist Updated 2 months ago November 27, 2023
For ski areas, snow reporting should be as simple as...
- Measure the snow that fell over the past 24 hours at 6:00 AM local time.
- Record the 24-hour snow report and add it to the season snowfall.
- Share the 24-hour snow report, along with the season snowfall.
- Share base depth, terrain information, and open/close status.
Unfortunately, sometimes there are errors in the snow report data. Below we outline the issues with snow reports and discuss how we attempt to fill in missing data.
How is snow measured at ski areas?
Most ski areas gather and share their snow report data from a mid-mountain elevation and record one 24-hour snow report every morning at nearly the same time.
Reasons for inaccuracies or inconsistencies in the data include the measurement of snow at the base or summit elevation and not mid-mountain, as well as measuring snow multiple times per day and not once per day in the morning.
Another reason for inaccuracies can be a miscommunication from the ski patrol or snow safety manager that initially makes the measurement to the communications team that records and shares the 24-hour snow report and season snowfall with the public. While people grumble that ski areas lie about snow measurements, our observation during 15+ years is that nearly all errors occur due to a lack of attention to detail and honest mistakes.
There is no standard procedure or protocol across the ski resort industry for how, when, and where to measure and share snowfall, and this lack of standardization across hundreds to thousands of ski areas is what contributes to inaccuracies in the snow report data.
What is OpenSnow doing to fix it?
We rely on the ski areas to send us the correct 24-hour snow report.
During most days of the ski season, most North American ski areas send OpenSnow a 24-hour snow report, the open/close status, terrain information (trails and lifts open), and a base depth measurement.
Example: Crested Butte
However, sometimes we receive incorrect data or no data at all.
We do contact ski areas to talk with them about their snow reporting and to encourage them to consistently measure and report snow, but ultimately we do not control the snow reporting process.
If we do not receive a 24-hour snow report, we have a backstop in place, which is to create an estimated 24-hour snow report.
Estimated 24-Hour Snow Reports
If we do not receive a 24-hour snow report from a ski resort by 6:00 AM local time, we use our proprietary blend of global and high-resolution weather model data to estimate how much snow fell between 6:00 AM on the previous day and 6:00 AM on the current day.
We then mark this estimated 24-hour snow report with a yellow line and an "Estimated" badge.
Example: Sugar Bowl
The estimated 24-hour snow reports are exactly that – estimates. Sometimes these estimates are very accurate, most of the time they are in the ballpark, and sometimes they are much different than the actual snow total.
We also verify each resort-submitted 24-hour snow report against our estimated 24-hour snow report. This way we are as transparent as possible and it gives you the option to double-check the report if we think it's significantly above or below our estimate.
Example: China Peak
The 24-hour snow reports that we receive from ski areas are free to view on OpenSnow, and the estimated 24-hour snow reports are available only to All-Access subscribers.
These 24-hour snow report estimates are also available for locations that have no official snow reports, like backcountry locations and even at your house, and you can view estimates for any location using Forecast Anywhere.
Estimated Season Snowfall
The Snow Season (or Water Year) is defined as between October 1 and September 30 in the Northern Hemisphere and between April 1 and March 31 in the Southern Hemisphere.
We wish that creating the season snowfall number would be as easy as recording the 24-hour snow report every morning of the season and then simply adding these numbers.
However, the season snowfall number can be incorrect for the following reasons:
- Some ski areas forget to report snow on some days.
- Some ski areas report an incorrect snow measurement on some days.
- Some ski areas measure new snow only when they are open.
In order for us to show a season snowfall number for every location, which includes snowfall for every day of the snow season, we add the daily 24-hour snow reports that we receive from the ski areas and then we add the estimated 24-hour snow reports for days when we do not receive the 24-hour snow report from the ski area. This method results in our ability to provide a season snowfall number for every location.
Example: Alta Ski Area
For ski areas that publish a season snowfall number that we trust, we may manually adjust our season snowfall data to match the ski area. In other cases, the estimated season snowfall number on OpenSnow should reasonably approximate the season snowfall, often within about +/- 20%.
BUT, here's the disclaimer: The season snowfall number should NOT be quoted by resorts or the media as official data, nor should it be used for official climate statistics.
What About Base Depth, Terrain Status, and Open/Close Status?
Similar to snow reports, we rely on ski areas to send us this information every morning during ski season. However, ski resorts occasionally fail to send us this data in which case the information we display for the ski area will be inaccurate or outdated.
Unfortunately, there is nothing we can do about this as we are unable to manually check the accuracy of this data for hundreds to thousands of ski resorts every morning.
Therefore, on each ski resort's forecast page on OpenSnow, we provide a link to the resort's snow report and terrain status web page.
You can find this link on any resort's forecast page on OpenSnow by going to Snow Report > View the report on the resort's website.
Snow does not fall in an even 'blanket' across a mountain, so it is normal for one area of a mountain to have a lot more or a lot less snow than another area. This is yet another reason why snow reporting is tricky.
We hope that you now have a greater appreciation of how the snow report numbers are generated here on OpenSnow and why they might at times be inaccurate.
Still Have Questions?
Send an email to [email protected]