Two EF1 Tornadoes Confirmed Northeast of Edmonton From Monday, May 26th, 2025

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Two EF1 tornadoes have been confirmed in Alberta from May 26th, 2025 by the Northern Tornadoes Project (NTP). Thankfully, there were no injuries with these two tornadoes. The strongest of the two was on the ground for an impressive 21.2km and had estimated wind speeds of 175km/h. The two tornadoes touched down near Lac la Biche and left behind lengthy, narrow paths of damage, including a partially removed roof from a home and numerous snapped and uprooted trees.

Investigators from the NTP conducted thorough ground and drone surveys on May 28th and noted that Alannah and Patricia from our own Instant Weather team helped get their team deployed quickly. The NTP wrote: “Thanks to Alannah and Patricia at Instant Weather for their initial (late-night) alert to the damage, allowing us to get our team out faster!” We at IW are grateful that we were able to help NTP with their investigation and super thankful that no one was injured in these two tornadoes. The NTP meticulously documented the aftermath and their findings paint a clear picture of the two separate twisters that tore through the region.

The Atmore Twister – A Lengthy Path of Damage

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The first tornado, designated the "Atmore" event, began its destructive journey at approximately 7:00 PM MDT (0100 UTC) on May 26th.

Final EF-Scale Rating: EF1

Estimated Max. Wind Speed: 175 km/h

Track Length: A substantial 21.2 km

Max. Path Width: 300 m

Motion: From the Southwest (approx. 220 degrees)

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This twister carved a significant path, causing notable damage to homes near Atmore and Rossian (north of Plamondon). Reports detailed structural impacts and the NTP survey confirmed these, along with extensive tree damage. Satellite imagery review also highlighted the visible tree damage along its long, narrow track. Luckily, despite the substantial property damage, no injuries were reported.

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The Avenir Tornado – A Shorter, Wider Impact

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Just 25 minutes after the Atmore tornado began, a second EF1, named the "Avenir" event, touched down further to the northeast at approximately 7:25 PM MDT (0125 UTC).

  • Final EF-Scale Rating: EF1

  • Estimated Max. Wind Speed: 150 km/h

  • Track Length: 6.43 km

  • Max. Path Width: A slightly wider 370 m

  • Motion: From the South-Southwest (approx. 205 degrees)

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While shorter in track length, the Avenir tornado left a clear signature, primarily impacting forested areas near the community of Avenir. Satellite imagery initially revealed its narrow path of tree damage, which was later confirmed and documented by the NTP's ground and drone survey. As with the Atmore event, no injuries were reported in connection with this tornado.

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Understanding the Findings

The Northern Tornadoes Project plays a crucial role in confirming, classifying and analyzing tornado damage across Canada. Their use of satellite imagery, followed by on-the-ground surveys with drones, allows for precise classification and understanding of these powerful weather phenomena.

These EF1 tornadoes, with wind speeds reaching up to 175 km/h, serve as a reminder of the potential for severe weather in Alberta. While not the most powerful on the Enhanced Fujita (EF) Scale, they are certainly capable of causing significant localized damage, as evidenced by the events near Lac la Biche.

Find out more & get notified

  • You can view precise tracks of these tornadoes and explore other Canadian tornado and downburst events on the interactive NTP Dashboard.

  • Always have a plan for severe weather and download our free app Instant Weather to get notified of any alerts from Environment Canada or any custom updates from the IW team regarding rotation, funnel cloud reports, etc.

Ontario’s First Confirmed Tornado of 2025: EF0 Touches Down Near Woodstock Last Week

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Ontario’s tornado season has officially begun. The first confirmed tornado of 2025 touched down during the early morning hours of May 16th, just south of Lakeside, Ontario, northwest of Woodstock.

The tornado developed along the leading edge of a line of storms that had tracked into the province from Michigan.

While this EF0 tornado near Lakeside was the first confirmed in Ontario this year, it wasn’t the first in Canada.

According to the Northern Tornadoes Project, this brings Canada’s confirmed tornado count for 2025 to five.

The season began with an EF0 tornado in Alberta in early April, followed by an EF1 in Quebec later that month. Just one day before the Lakeside event, two EF0 tornadoes were confirmed in Manitoba on May 15th.

With peak season still ahead, this serves as a timely reminder that severe weather can happen quickly and under conditions that don’t always look extreme on the surface.

Even low-end risks deserve attention, especially when storms arrive at night, when people are less likely to be tuned in.

The Tornado: A Narrow but Confirmed Touchdown Near Lakeside

Survey map for the Lakeside EF0 tornado (source: Northern Tornadoes Project)

According to the Northern Tornadoes Project (NTP), the tornado developed just south of the village of Lakeside, approximately 25 km northwest of Woodstock. It touched down around 3:00 AM EDT, shortly after a squall line of thunderstorms entered the region from the west.

Drone photo of worst damage point featuring multiple snapped conifers (source: Northern Tornadoes Project)

Damage was limited to trees and a power pole, with no injuries reported. The tornado was assessed as an EF0, with estimated maximum wind speeds of 115 km/h. It travelled a distance of 3.6 km, with a maximum path width of 160 metres, moving generally from the west-southwest (255°).

Radar data shows possible rotation near lakeside (source: iw pro)

Radar imagery at the time showed a compact area of low-level rotation, but due to the storm’s embedded structure and the overnight timing, the event went unwitnessed until damage was reported later that day.

The NTP conducted both ground and drone surveys on May 20th to confirm the tornado’s track and intensity.

This information is sourced from the Northern Tornadoes Project’s full report, which can be found here.

Survey map showing the location of the EF0 downburst (black oval) and collected data (source: Northern Tornadoes Project)

In addition to the confirmed tornado near Lakeside, the Northern Tornadoes Project also verified a separate EF0 downburst near Chatham from the same storm system.

The downburst occurred around 2:15 AM EDT, roughly 45 minutes before the tornado, and caused significant damage to several barns, farm buildings, power poles, and trees.

While similar wind damage was reported across parts of Southwestern Ontario—from Windsor to Shrewsbury—only the enhanced damage south of Chatham was surveyed.

Wind speeds were estimated to have peaked at 130 km/h, placing the event at the high end of the EF0 scale. No injuries were reported.

Timeline: Forecast Leading Up to the Tornado

Forecast models began flagging the potential for severe storms several days in advance, particularly in Deep Southwestern Ontario, where the environment appeared favourable for severe weather.

Instant Weather and the U.S. Storm Prediction Center both noted the possibility of tornadoes — albeit marginal — due to the timing and nocturnal nature of the storms. This provided over 24 hours of advance notice about the potential for severe weather.

Despite the lower-end risk, one storm managed to spin up a brief EF0 tornado shortly after 3:00 AM on May 16th.

Instant Weather first highlighted the tornado potential on Wednesday afternoon, referencing the Storm Prediction Center’s forecast and the setup in Michigan and Southwestern Ontario:

The following morning, just under 24 hours before the confirmed tornado, Instant Weather once again flagged the risk.

This time, the post specifically mentioned that a 2% tornado risk extended into Sarnia, Chatham, Grand Bend, and as far northeast as London, placing the affected area firmly within the broader risk zone:

Later Thursday afternoon, a forecast was issued by Instant Weather calling for the potential of isolated tornadoes overnight. The forecast map outlined a marginal risk that included the area near Lakeside, where the tornado would eventually touch down:

Around 1:47 AM, just over an hour before the tornado touched down, Instant Weather sent out a custom notification for the London area, referencing minor rotation and clearly stating that “an isolated tornado cannot be ruled out”:

At 2:55 AM, Environment Canada issued a Severe Thunderstorm Warning, which included a note that severe thunderstorms can produce tornadoes. This came approximately five minutes before the tornado would touch down near Lakeside

Finally, live coverage was underway on Instant Weather’s YouTube channel during the time the tornado developed around 3:00 AM, as the storm moved through Oxford County.

Nocturnal Thunderstorm Threat With Damaging Wind Gusts and Isolated Tornado Risk for Southwestern Ontario Tonight

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updated map - 10:50 PM (CLICK HERE FOR THE PREVIOUS MAP)

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UPDATE (10:50 PM):

We’ve been closely tracking the line of storms developing across Michigan, and it’s now set to move into Deep Southwestern Ontario over the next few hours.

Based on the latest model data, current environmental conditions, and how well the storm is holding together despite the lack of daylight heating, we believe there’s enough evidence to upgrade parts of Deep Southwestern Ontario to a ‘strong’ (3/5) risk—mainly due to the potential for intense wind gusts.

Large hail up to the size of toonies is also possible, and we can’t completely rule out an isolated tornado.

We’ve also extended the ‘slight’ (2/5) risk further inland to include areas like Goderich and London, as new data suggests the line could stay fairly strong as it tracks deeper into Southwestern Ontario during the pre-dawn hours. Again, damaging wind gusts remain the primary threat.

The line is expected to cross the border just after midnight, with the severe threat gradually tapering off but still continuing until around 3–4 AM.

ORIGINAL FORECAST

While storm season has had a quiet start in Southern Ontario, things are beginning to ramp up with a late-night storm risk expected between Thursday evening and early Friday morning. A strong line of storms is forecast to form across Michigan late tonight, initially beginning as discrete supercells over parts of Wisconsin and Illinois.

Based on the latest guidance, these storms are expected to organize into a more linear structure as they track eastward, eventually crossing into Southwestern Ontario sometime just after midnight. While they’ll likely lose some of their strength after dark, especially without daytime heating, the atmosphere may still be supportive enough for them to maintain some intensity as they move into our region.

That said, there’s still a fair amount of uncertainty about just how strong this line will be once it crosses the border, and how quickly it might weaken as it tracks northeast through the early morning hours of Friday.

The biggest concern with this system is the potential for damaging wind gusts. This squall line will stretch from the Upper Peninsula of Michigan all the way down through Ohio as it enters Ontario, which could lead to widespread impacts. Areas from the Bruce Peninsula all the way down to Deep Southwestern Ontario are at risk of strong winds embedded within the line.

The highest risk appears to be in Deep Southwestern Ontario, where the line will first cross into Ontario. Regions like Windsor, Leamington, Chatham, and Sarnia are most likely to experience the strongest part of this line. While damaging wind gusts are the main hazard, we also can’t completely rule out the chance for hail and even a brief tornado, especially if the storms arrive a bit earlier than forecast.

Hail up to the size of quarters is possible, and while the tornado risk is considered low overall, it does exist. The biggest concern here is that this is a nocturnal threat. If a tornado were to develop overnight, it would be harder to spot and could be rain-wrapped, making it even more dangerous. That’s why it’s so important to stay alert and have a way to receive warnings while you sleep.

SIMULATED RADAR - MAP FROM WEATHERBELL

Storm development will begin with discrete cells over Wisconsin and Illinois, likely forming into a long line around 8–10 PM near Chicago and across Lake Michigan.

The timing of this formation is crucial. If the line develops sooner and sweeps across Michigan quickly, it could result in a more robust severe risk for Deep Southwestern Ontario, where the environment is more favourable before midnight.

No matter the timing, damaging winds remain the most likely outcome with this type of linear storm setup.

SIMULATED RADAR - MAP FROM WEATHERBELL

As of now, future radar models suggest the storms will cross into Ontario between 1 and 2 AM, hitting areas like Windsor and Sarnia first before stretching further northeast. However, there’s still wiggle room in this timing. It could arrive earlier and stronger, or later and already weakening before reaching our region.

ESTIMATED TORNADO ENVIRONMENT - MAP FROM WEATHERBELL

While widespread wind damage is the primary concern tonight, there is some minor tornado potential—especially in Essex County just after midnight. Again, the odds are low, but not zero.

Because of the overnight timing, it's extra important to have notifications enabled on your phone or weather radio. Make sure you have a way to receive alerts while you're asleep in case a warning is issued. Our free app is a great way to instantly get Environment Canada alerts, along with our custom notifications issued for your exact location.

SIMULATED RADAR - MAP FROM WEATHERBELL

The line of storms is expected to continue northeast through the early morning hours, bringing heavy rain, gusty winds, and frequent lightning to much of Southwestern Ontario and parts of the Greater Toronto Area between 3 and 6 AM.

While the line should gradually weaken during this time, it could still pack a punch in some localized areas. There’s some uncertainty around how long it will be able to hold its strength since the atmospheric environment in Ontario is notably weaker than what the storms had access to in the U.S.

Latest model runs show the system likely fizzles out once it reaches Lake Simcoe, meaning Eastern and Central Ontario probably won’t see much beyond a few scattered morning showers or storms.

Another round of storms is possible Friday afternoon and evening, particularly for Eastern Ontario and parts of Deep Southwestern Ontario. We’ll have more details on that in a separate update.

As it stands, the highest storm risk tonight is in Deep Southwestern Ontario, where we currently have a slight risk (2/5) for severe weather. The main hazard is damaging wind gusts between 12 and 6 AM, though isolated tornadoes and hail up to the size of quarters are also possible.

For the rest of Southwestern Ontario and the Golden Horseshoe, the risk is lower—a marginal (1/5) severe threat—with isolated pockets of wind damage being the most likely outcome. There’s also a very low tornado risk along the Lake Huron shoreline as the line initially pushes into the region. Hail up to the size of nickels could accompany some of these storms.

In addition to the overnight threat, a few isolated pop-up storms are possible during the late afternoon and early evening across parts of Grey-Bruce. While these are not expected to be severe, funnel clouds are possible, including a low-end risk of a landspout tornado. See our custom notification for more on the funnel cloud setup.

Stay weather-aware tonight. Keep your devices charged, notifications turned on, and have a plan in place just in case you need to take shelter quickly. We’ll continue to monitor the latest data and provide updates as the situation evolves, including a possible live stream later tonight.