Missed' EF2 tornadoes in Canada and the role of radar

The Northern Tornadoes Project (NTP) at Western University is responsible for detecting, assessing and documenting all tornadoes that occur across Canada.

In 2022, the NTP began using the national tornado event data along with tornado watches and warnings issued by Canada’s national meteorological service to assess alerting performance. While a gradual improvement in overall score has been noted over the three assessments covering the periods 2019-2021, 2022, and 2023-2024, there continues to be a significant number of EF2 tornadoes each year that are not warned.

At the same time, Environment and Climate Change Canada recently completed an upgrade to the country’s weather radar network, moving from C-band to S-band radars, significantly increasing Doppler coverage, decreasing the time between scans to 6 min (from 10 min), and adding polarimetric capabilities.

In this study, we take a closer look at the 29 'missed' EF2 tornadoes from 2022 to 2024 and in particular at the role of radar since radar is the primary diagnostic tool for the warning meteorologist. Keep in mind of course that weather radars can rarely detect a tornado, but are capable of detecting storm-scale rotation with the parent storm, within which tornadoes can develop.

Despite the improvements to the radar network, there appear to be a number of ways in which radar scanning, data, algorithms and availability are related to the absence of tornado warnings for these EF2 tornadoes. In other cases, no warning was issued despite the radar providing ‘textbook’ detection of tornado-related features. All of these will be explored in the presentation, with representative examples provided.

Potential approaches for enhancing radar capabilities in Canada in order to address these issues will also be discussed.