One Year Later: Reflecting on the Impact and Recovery from the Historic May 2022 Canadian Derecho

Storm damage in Uxbridge, OntariO - Photo courtesy of the Northern Tornadoes Project (NTP)

On May 21, 2022, Southern Ontario and Quebec were hit by a devastating derecho, an event that would be ingrained in the memories of millions of Canadians. Described as one of the most impactful thunderstorms in Canadian history, the derecho wreaked havoc across a 620-mile-long track, resulting in unprecedented levels of destruction and loss. Now, a year later, we look back at the event, the recovery efforts, and the ongoing investigations into this historic event.

Understanding Derechos

A derecho is a type of violent, fast-moving windstorm associated with severe thunderstorms and characterized by a long-lasting, straight-line windstorm that spans hundreds of kilometres. These storms are not common in southern Canada. Typically, derechos in this region form during mid-summer when a hot and muggy air mass covers the Midwest and Ohio Valley. These derechos tend to develop on the northern boundary between the hot, humid air and cooler, drier air where there is also an elevated mixed layer.

The Birth of a Storm

The May 2022 derecho was born out of a persistent May heat wave that had initially enveloped the U.S. and gradually expanded northwards to cover Southern Ontario and Quebec. Unseasonably warm temperatures, more akin to July, laid the groundwork for this high-impact storm. The storm system first formed south of Chicago and, by the morning of May 21, had developed into significant wind-producing thunderstorms in Michigan. The derecho coalesced into a bow front approximately 100 km wide as it hit London, Ontario, continuing to intensify as it moved eastward through the region.

The Aftermath

The storm caused widespread damage to residential and commercial properties and public utility infrastructure. At least twelve people lost their lives, primarily due to falling trees, while an estimated 1.1 million customers were left without power, some for a week following the storm. The financial cost was staggering, with the estimated insured damage totalling C$875 million, making it the sixth-costliest natural disaster in Canada in terms of insurance claims,

The recovery process was equally monumental. Southern Ontario, in particular, was hit hard by the derecho. From Ottawa to Toronto, communities pulled together to repair and rebuild the damaged properties and restore a semblance of normalcy. One year on, the effects of the derecho can still be felt, both in the physical landscape and in the emotional toll taken on the inhabitants of the affected areas.

Ongoing Investigations

damage path from the northern tornadoes project

The Northern Tornadoes Project (NTP), an organization devoted to the study of tornadoes and severe weather in Canada, has been diligently investigating the May 2022 derecho. As per their latest findings, the derecho caused 12 fatalities and 12 injuries. Their research suggests that the number of victims may increase as the impacts of the storm continue to be investigated.

The May 2022 derecho also marked the first time that Environment Canada used a new broadcast-intrusive through the AlertReady system to deliver a severe thunderstorm warning due to wind gusts exceeding 130 km/h. This new warning capability was crucial in mitigating the number of casualties, which could have been even higher had the new system not been utilized.

Reflection and Lessons Learned

As we reflect on the one-year anniversary of this historic event, the combined efforts of communities, governmental organizations, and scientific bodies like the NTP have given us valuable insights and lessons. The 2022 derecho serves as a stark reminder of the power of nature and underscores the importance of weather forecasting, community preparedness, and ongoing scientific research in mitigating the impact of such severe weather events.

The recovery from the May 2022 derecho continues, as does the scientific investigation into this unique storm. The data gathered and the lessons learned from this event will undoubtedly contribute to our understanding of these severe weather phenomena and guide our preparations and responses for future events. The legacy of the May 2022 derecho will be one of resilience, community spirit, and scientific discovery.