Researchers from Canada’s Institut National de la Recherche Scientifique (INRS) are developing a sensor that uses infra-red radiation to track snow depth daily.

Roofs collapsing under heavy snow, mini-avalanches in cities and flash floods are just some of the winter headaches that could be resolved if there were a better way to track snow cover. With that in mind, PhD student Mohamed Karim El Oufir, research assistant Anas El Alem and professor Karem Chokmani from INRS are working on a sensor that can track snow depth daily.

The findings have been published in the journal Remote Sensing.

Snow is a fact of life in Québec and everywhere else in Canada. But it is difficult to track.

“The conventional method is to take snow samples, but it gets labour intensive and expensive when you have to travel over a large area,” said Chokmani. “For obvious logistical reasons, measurements are only taken once every two weeks. With more frequent and more accurate tracking, we would know when it is time to clear the snow off the roof and also be able to determine whether melted snow has reached peak volume and poses a flood risk.”

The research team plans to build a low-cost prototype sensor in the next few months. The device will measure snow density based on depth, every day.

Chokmani said this cheaper type of sensor would make it possible to cover a larger area while keeping travel and labour costs down. The probe only needs to be installed once and connected to a satellite via a mobile phone for easy data collection. Data are processed using an algorithm developed via a cloud-based calculation, and the results are sent to users in real time. There are also plans to use solar energy to power the device.

Other sensors are available on the market, but most are heavy and expensive. They usually only measure overall snow density, not density by strata.

“Snow settles in layers of varying densities, and these layers change over time,” said Chokamani. “It is very important to have data for all layers of snow, particularly for avalanches.”

Because the spectral behaviour of snow is linked to its density, the INRS team has developed sensor technology that uses infra-red radiation reflectance. However, according to Chokamani, the same index could be linked to various densities, based on the age of the snow.

In previous research, the team showed how to categorise snow by age. That technique will offset any ambiguous link.

“Fresh snow has small grains that diffuses infra-red radiation,” said Chokmani. “As it ages, snow forms bigger clusters and its spectral behaviour changes. By separating snow into categories, we can determine its precise density, because the link becomes unequivocal. This research is promising for better management of Québec winters.”

INRS is a university dedicated to graduate level research and training. Since its creation in 1969, it has played an active role in Québec’s economic, social and cultural development and is ranked first for research intensity in Québec and in Canada. The INRS community includes more than 1500 students, postdoctoral fellows, faculty members and staff.