Canada’s snow problem

Shoddy snowfall data is filling Environment Canada’s database

There are two main questions often asked about winter storms — how much snow will we get, and how much snow did we receive?

The latter is being called into question more often, and for good reason.

There are growing concerns from not just meteorologists and climate scientists but citizens that official snowfall data is simply, not accurate.

The problem was highlighted this past winter but has been ongoing for several years. Nav Canada operates weather stations and employs weather observers at most major airports. Environment and Climate Change Canada relies on their data for current and past weather conditions.

During snowfall events, Nav Canada’s observers take hourly measurements with a ruler.

It’s also standard practice to melt snow to determine the amount of liquid it contains. This is called the snow-water equivalent and is an important part of weather forecasting and post-storm analysis.

But errors or miscalculations are happening consistently when it comes to snowfall and snow-water equivalent in our region.

In one example, all of Halifax’s 133.6 cm of snow in February 2024 can be converted to about 133.6 mm of liquid. In short, each event was estimated as having a 10:1 ratio, meaning 10 cm of snow melts to 1 cm of liquid.

That was not the case for each snowfall event, which means either snowfall was measured and divided by 10 to get precipitation in millimetres or precipitation was multiplied by 10 to get snow in centimetres without a ruler measurement.

Regardless, some of this data is incorrect.

Another example in Gander, N.L., was a 46.6 cm snowfall with a total precipitation of 29.1 mm. That’s approximately a 16:1 ratio, which indicates the snow contains less liquid and is fluffier. The problem? This was a wet snow event, so it’s unclear where this high ratio came from.

In short, poor practices are feeding inaccurate snowfall data into our official weather records.

Accurate record-keeping is crucial to not just daily weather records but observing how our climate is changing with time. These poor practices are allowing inaccurate data to be stored in official databases used for challenging records and calculating climate normals and trends.

“ECCC is aware of the quality concerns regarding snowfall data,” spokesperson Samuel Lafontaine told Saltwire, adding that ECCC is working to leverage test sites to quantify performance and limitations of automated snowfall measurements.

Lafontaine also said ECCC uses quality control processes to assess the quality of its weather data — including snow observations, and that corrections are made where possible with data undergoing subsequent review and validation before being distributed.

However, on multiple occasions mentioned poor or inaccurate snowfall measurements can be found in their public records database.

For Nav Canada’s part, whose core mandate is aviation weather, spokesperson Maryam Amini tells Saltwire that several airports in Atlantic Canada, including Halifax Stanfield, Charlottetown, St. John’s, and Gander, don’t have an instrument called a Nipher snow gauge to capture and measure snow-water equivalent.

Navcan and ECCC confirm that Nipher snow gauges are being reinstalled where possible to allow its observers to calculate the snow-water equivalent.

The problems surrounding these snowfall measurements have people turning to the Community Collaborative Rain, Hail and Snow Network (COCORAHS) for more reliable observations. Hobbyists follow strict guidelines and take observations of rain and snow to input into an online database.

Because it’s a citizen science program, the reports are deemed unofficial and can’t be used for official record keeping. Environment and Climate Change Canada also said despite ingesting the data, it has no plans to use it for their climate products.

“ECCC is however, undertaking a review of its Cooperative Climate Network (CCN) program to determine if other opportunities exist to supplement its automated weather station data with observations from volunteers,” Lafontaine said.

There is little that forecasters and the public can do about this except call for change. Environment and Climate Change Canada is a federal agency, which means concerns can be brought forward to local Members of Parliament.

Something as small as a snowfall measurement is now more important than ever.

We can’t afford to have shoddy snowfall data put into our record books.