A Comparison of Two Historic Winter Storms in Autumn: Alberta and Manitoba

It's been a very active and early start to the winter season in the Prairies, as two significant winter storms broke records and impacted millions of people before Thanksgiving Monday. In the end of September, Waterton Lakes National Park and adjacent areas of Montana were blanketed under a metre or more of snow, and on Thanksgiving long weekend, a powerful Colorado Low wreaked havoc across southern Manitoba as heavy, wet snow and blizzard conditions lashed parts of the province. Here, we quickly review the characteristics of each storm, before comparing the two. 

Southwest Alberta, September 27-30

A multi-day event resulted from a stalled upper low over the NW US, which led to the superimposition of several potent lifting mechanisms over southwest Alberta. The storm would tap moisture from the east and cold Arctic air from the north, piling it all into the terrain beneath the northeast quadrant of the upper low. A depth of 95cm was reported in Waterton Townsite on Sunday evening at 850PM, with 95cm also being recorded the following morning despite nearly 10cm of additional accumulation in the overnight - which was suggestive of the ongoing effects of compaction. Therefore, total snowfall accumulations likely exceeded 100cm in Waterton Park and on the immediately adjacent plains to the east - where at least one other report of 92cm depth was received WNW of Cardston. Even greater amounts were reported south of the border. Click this link to see my discussion breaking down the forecast for this event.

Snow blankets Waterton Townsite.

95cm depth as of 850PM Sunday. 

Graphic from the NWS showing snow totals. Areas with 4 feet of accumulation may have occurred along the US border in the hills SW of Cardston.

Heavy snow also occurred elsewhere across southern Alberta, with Calgary breaking its all-time daily September record on the 29th, with 24.6cm of snow. As Weatherlogics' chief scientist Scott Kehler pointed out, this was the second year in a row in which all-time daily records for a given month were broken in Calgary - as the the all-time daily record for October in the city was also broken last year (2018), when the city was walloped by 32.8cm on the 2nd day of the month.

The southern foothills and front range of the Rockies were particularly hard hit, but very heavy totals fell toward Lethbridge as well. 

Aspen trees in full summer foliage bending under the weight of the snow.

The heavy snow had major impacts to travel in southern Alberta, with numerous vehicles sliding into ditches on Sunday in particular. A few minor power outages were reported, and impacts to ranching and the fall harvest where it was still ongoing were also significant.

An H3 almost being swallowed by snow drifts in the ditch along Highway 22 west of Nanton, where many vehicles slid into the ditch.

Beautiful scenes in low light near Chain Lakes, where over 80cm fell, and was sculpted into large, dune-like drifts. 

Not a day for a picnic at Chain Lakes.

For me personally, it was the heaviest single snowfall I've encountered, and it was fun to document the amazing scenes I found around the townsite. Click here to see some reactions of some of the few folks left in town, here to see me wade through really deep snow, and here for a recap of the storm.

Waist-deep in snow reporting.

Southern Manitoba, October 10-12

A powerful Colorado Low with textbook mid-latitude cyclone structure would rapidly deepen as it moved north-northeastward up a baroclinic zone out of the US Heartland, before undergoing occlusion in NW Minnesota and nearly stalling out while bringing most impactful weather of its life cycle to southern Manitoba. A retired ECCC meteorologist wrote this excellent blog on the storm, which goes into even greater depth than I will here regarding specifics and impacts of the storm. As well, here is a link to my post regarding the forecast for the storm.

Whiteout conditions were common on Friday in parts of southern Manitoba.

Heavy, wet, wind-driven snow fell across southern parts of the province, with Winnipeg picking up a storm total of 34cm in what would become the greatest October snowstorm in the city's history - and the worst winter storm since the blizzard of April 1997. Elsewhere, a report of 74cm was picked up in Carberry via social media, and as Rob pointed out in his blog, a CoCoRaHS observer south of Morden reported 90cm. The snow largely had SLRs less than 10:1, which was a main contributing factor to the scale of damage that resulted from the storm. The storm was also accompanied by strong winds, with gusts of 100km/h being picked up at Oakpoint, and 94km/h at Portage La Prairie. Significant drifting occurred in areas of the far south, where the combination of terrain-enhanced snowfall totals and strong winds could transport maximum amounts of snow.

Elevated terrain features along the Manitoba Escarpment have enough relief to influence patterns of precipitation.

A portion of a summary of the storm from ECCC.

As expected, the storm had numerous significant impacts, with widespread damage to trees and power infrastructure. The City of Winnipeg said roughly 30000 of its trees were damaged, where a falling tree branch also injured two people - one of those critically. At one point, upwards of 50000 customers were without power, with the entire city of Portage going dark for a period of time, as nearly 3000 hydro poles and several more transmission towers went down across southern Manitoba. Most highways - including the Trans-Canada between Winnipeg and Brandon - were closed during the worst of the storm on Friday and Saturday, barring the travel of thousands of residents on Thanksgiving weekend. The city of Portage opened the Herman Prior Center as an emergency shelter to travelers in need of lodging, as highways were closed and hotels were full. Delays and cancellations to flights at Winnipeg Airport also occurred, with one plane becoming stuck on a taxiway in the heavy snow - which impacted the western suburbs of the city more heavily than those on the east side.

The Manitoba Hydro outage map was lit up like this for a long period of time.

A common scene around southern Manitoba.

Longer stretches of downed hydro poles on the west side of Portage than I've ever seen from any tornadic or straight-line winds.

Adding insult to injury, the storm also came a time when southern Manitoba was already excessively wet, prompting officials to open the Red River Floodway to divert water around the city of Winnipeg for the first time in fall in the city's history.

Courtesy Agriculture Manitoba, this map reveals how wet it has been this warm season - with much of this only coming during the first part of fall.

Winter storm chasing requires that one finds reliable shelter, such as a hotel, as close to the intersection of a major population center and severe weather as possible, and then hunkering down there for the duration of the storm. It also requires topping up with gas and carrying emergency survival gear in the event that the power goes out at your hotel or you get stranded. The power did go out at my hotel - as well as in the rest of the city, which made things quite interesting for a time. Things really ramped up on Friday night, with power flashes lighting up the skies amid raging blizzard conditions for several hours. Even the road from town to my hotel near the highway became quite exciting later in the evening. At one point while filming a camera hit, a wind gust came up and knocked my camera over. See that moment here. 

A screenshot of the moment my camera was going down. Nooooooo....

Comparing the Two Storms

Both storms were well-forecast and communicated by the weather enterprise, with model guidance having a pretty good handle on the outcome of both. In the case of Waterton, both NWP and pattern recognition gave fairly high confidence for the potential of significant snowfall totals in southwest Alberta. Similarly, there was a fairly high confidence that record-breaking snowfall accompanied by strong winds would occur in part of southern Manitoba. In both cases, the effects of stalling both prolonged lift and maximized impacts. 

Despite southwest Alberta having much greater snowfall totals, impacts overall were much less for a number of reasons - even with trees in leaf in both locations. The liquid equivalent in the precipitation accumulation bullseyes were likely similar between the two storms, meaning the snow-to-liquid ratios were vastly different - and this had major implications on the degree of impact that the storms had. SLRs near 10 or 15:1 in the higher elevation, colder Alberta storm meant cooler profiles, which translated to both greater snowfall totals and lesser impact to trees and powerlines. The snow was drier and less sticky, which tended to sluff off trees and powerlines in the wind - unlike in Manitoba.

Wind was also more of a factor in Manitoba, as the stronger dynamics of the potent, occluding Colorado Low resulted in much more powerful winds at the surface that alone could be sufficient at breaking tree limbs leading to power outages in the absence of excessive snow loads. Indeed, when combined with strong winds, the concrete-like snow clinging to high-tension powerlines likely increased tensile forces to the point that large, steel transmission towers failed and buckled over.

Heavy, wet snow weighs down the lines.

The tension of the lines under snow load accompanied by strong winds caused hydro poles to snap.

A crumpled transmission tower in Portage.

That can't be a quick fix! High-tension lines are draped right down in the lake.

Of course, the population of the hardest-hit areas of southwest Alberta pales in comparison to that of the hardest hit areas of southern Manitoba, which alone would reduce impacts. Less urban areas also means less trees in urban areas would likely impact the power grid overall. Trees in general are few and far between in the high and dry environment of Chinook country along the eastern slopes.

And finally, the time of year is also likely a factor in the severity and degree of impact of these storms. Not only are trees still in leaf, making them more vulnerable to the effects of wind and snow loading, but profiles overall are warmer - meaning the sticky, damaging type of snow is likely to be more common. Zonal temperature contrasts also become much greater in the fall, which can lead to much stronger dynamics of weather systems and resulting surface winds. More precipitable water also exists in the warmer columns of fall when compared with winter, when availability to sources of rich moisture is also greater than in winter. Combine the effects of stronger dynamics of weather systems and greater moisture availability, and all you need is a stalled system to create major problems.

As climate changes, more weather extremes are expected. In western Canada, many have asked "what happened to climate change?" in response to these early winter-like events, but these types of events might be the exact types of scenarios we might begin to expect more of going forward as the climate destabilizes. After all, a warmer Arctic (and Beaufort Sea in particular at the moment) could disrupt upper air patterns and leading to blocking and/or the displacement of Arctic air to more southern latitudes, where it can influence the nature and intensity of the very types systems we have been observing.

Looking Ahead to the Thanksgiving Weekend Winter Storm in Manitoba

A significant, and potentially historic October winter storm is set to impact parts of the northern Plains and southeast Prairies, as heavy wet snow and potential blizzard conditions could develop across the region on Friday and into Saturday as storm strength peaks during early occlusion.

Impacts

Given that the storm is expected to occur at the start of the Canadian Thanksgiving long weekend, impacts to travel will likely be significant. Highway travel could become difficult to impossible beginning early Friday and lasting into Saturday, and wind-driven snow leads to whiteout conditions across parts of southern Manitoba and North Dakota. All travel should be avoided during this time due to dangerous or impossible travel conditions and attendant risks of being stranded. Icing could also occur near the Red River Valley, resulting in slippery patches on roads there, prior to precipitation transitioning to snow.

Delays and possibly cancellations to flights are likely to occur at area airports. As well, heavy, wet snow could lead to tree damage, as many trees are still in foliage. This will also lead to a threat of power outages across the affected area.

Finally, a soggy Red River Basin from record-breaking fall precipitation will see potential flood conditions exacerbated owing to heavy precipitation totals. In fact, the Red River Floodway has already been opened for the first time ever in fall in Winnipeg - and while rivers aren't expected to crest their banks, high flows will continue to occur until they are projected to peak between October 17-20.

Meteorology

A truly classic Colorado Low, with textbook mid-latitude cyclone structure departs the Rockies and zips up the baroclinic zone across the northern Plains on Thursday and into NW Minnesota, when it begins to occlude on Friday. Well-developed airstreams will be observed as the cold conveyor belt wraps around the low, bringing heavy snow and possible blizzard conditions to its northwest, while the overrunning warm conveyor belt adds Gulf moisture to the system. Meanwhile, the dry conveyor belt descends as a dry slot and carves out the comma head of the system as it begins to occlude, and the surface low bottoms out sub 994mb per NAM guidance.

During early occlusion, very strong ascent occurs over southern Manitoba during the day on Friday, as DCVA, WAA, and ascent in the left exit region of a curved upper jet streak work in tandem. Embedded slantwise and upright convective elements will also occur on Friday, bringing locally very heavy precipitation rates and even a risk of TSRA/TSSN across the region around midday.

Thermodynamic profiles suggest that SLRs will generally be between 5:1 and 8:1 across southern Manitoba, and decreasing with eastward extent. However, as cold air wraps into the low post-occlusion, profiles should support higher SLRs with time later on Friday. DGZ depths will be unsubstantial. Meanwhile, low level stability profiles could permit some downward momentum transfer associated with a strong northerly low level jet stream on the order of 60-70 knots, which could yield wind gusts approaching 90-100km/h across south-central Manitoba on Friday, resulting in whiteout conditions as a potential blizzard develops causing extensive blowing and drifting snow - despite the snow being fairly wet. Moreover, expect to see enhanced snowfall totals along the elevated terrain features of the Manitoba Escarpment as a result of this storm.

The snow has already been occurring and will continue through Thursday along a deformation zone, where isolated bands could mean accumulations get a head start ahead of the main event on Friday and into Saturday. Winnipeg will continue to be the wildcard, as the rain/snow line sets up near or just east of the city. For what it's worth, SREF ensemble guidance as of Wednesday evening has been trending to cluster a greater number of members toward significant totals. Overall, downstream ridging will cause the system to stall somewhat - maximizing impacts for a longer period of time.

EPS ensemble guidance suggests the heaviest totals will occur near the international border SW of Winnipeg. While it is displayed here as 10:1 (and not including the effects of melting and compaction), I would not rule out at least a foot of snow falling in the bullseye. 

Looking Ahead to the September 27-30 Snowstorm

A significant, and potentially historic early fall snow storm could occur in parts of southern Alberta and northwest Montana this weekend, with the heaviest totals focused on the Waterton/Glacier region, owing chiefly to persistent upslope flow. Numerous daily snowfall records are expected to fall, with some record cold overnight lows immediately following the system being possible as well.

Impacts:

The storm is expected to have numerous impacts to travel, especially along and east of the Rocky Mountains, impacting the HWY 1 and 2 corridors west and south of Calgary, as well as along Highways 22 and 3 in southwestern Alberta. While the snow may not initially stick to road surfaces, temperatures will fall below freezing this weekend, and the snow will begin to rapidly accumulate – especially during overnight periods. Moreover, blowing and drifting snow may develop in places on Sunday and early Monday, reducing visibility to near zero. Travel is not advised in these conditions, especially given the fact that many folks don’t quite have their winter tires on yet. Standard snow plough safety will be required, including giving them lots of space and not passing them unless safe to do so. If travel is essential, pack along safety supplies including food, water, a cell phone, a source of light, blankets, and ensure the gas tank is full.

A hard freeze has yet to occur in the area set to receive heavy snowfall accumulations, so fall foliage has yet to peak in some areas. While it will not be as green as in the September 8-10, 2014 Calgary event, some damage to trees is likely, especially given the moderately strong winds that could develop during the day on Sunday. This could also have the undesired effect of tree limbs falling and endangering life and property below, as well as an attendant risk of power outages.

Impacts to agriculture are also expected, as the fall harvest is still underway and slightly behind in some areas of southern Alberta.

Meteorology:

The main weather maker responsible for this event will be an upper low that stalls during the weekend over the northwest US, tapping into both cold, Arctic air from the north, as well as a healthy source of moisture wrapping in from the east. The positioning of the low will place the area of concern beneath its northeast quadrant, where a number of lifting mechanisms will join forces and provide sustained lift supportive of the development of heavy snowfall. In fact, the setup is reminiscent of warm season heavy rainfall events that have been associated with flooding in southwest Alberta in the past. 

EPS ensembles indicating extremely large accumulations of snow in Waterton/Glacier. 

SREF ensemble mean has nearly 3 feet of snow near Browning, Montana by late Sunday evening.

As for the nitty-gritty details, DCVA and warm advection will occur in tandem across portions of the southwestern prairies and far northern High Plains, amid an environment of strengthening lower and mid-tropospheric easterly flow that will translate to sustained orographic ascent along the Rockies. As the low south of the border becomes more organized, moist, low level easterly flow comprising the cold conveyor belt will pile into the terrain, bringing heavy snow and strengthening east-northeasterly surface winds that will begin late Friday, and peak on Sunday and into early Monday. 

Strong, low level easterly flow ramps up on Sunday.

The storm will have ample access to moisture for record-breaking snow totals. 

Vertical temperature profiles will support snow-water ratios increasing to 10:1 or more by early Saturday along the front range, as a deep, DGZ develops aloft, with ample ascent through the profile to support continued development of heavy snow. Model QPF totals are impressive and in good agreement that substantially heavy snow could occur in a localized area along the front range near Waterton/Glacier, with lesser but still significant amounts over the plains to the east – especially as the system departs the Rockies and an area of heavy snow tracks near the international border to the northwest of the surface low. Snowfall totals will vary greatly along the northern fringe of this track, which is one of the factors in the uncertainty of snow totals in the Calgary area. 

A deep dendritic growth zone, as well as deep, easterly flow are indicated on this sounding for Sunday afternoon in extreme SW Alberta, resulting in strong ascent (among other forcing mechanisms) that leads to heavy snow development. Blizzard conditions will be possible across the main area of concern during the latter half of Sunday in particular.

As skies clear out following the passage of the system, strong radiational cooling over the fresh snowpack could lead to a few record low temperatures being set in parts of Alberta and Montana. Indeed, it will suddenly feel as though we have entered a time warp to late November, as persistent troughing across the region will delay the melt and keep things cool into the first part of October! 

That's a Wrap - 2019 Storm Season Highlights!

To date, 2019 was by far my most active. I put on about 40000km between 35 chase days in Canada, and 8 in the US. I logged 12 tornadoes, and got intimate with tennis ball hail near Vulcan. There were some memorable chases, with my favourite one being in Saskatchewan on my birthday (June 27) with friends.

A good chase in Saskatchewan is MONEY, as storms are big, skies are huge, and there are plentiful foreground elements of antiquity for photography. Never turn one down if you get the chance - especially in the south and southwest!

We provided lots of live coverage of storms this season, and documented the aftermath of 3 tornadoes and one straight-line wind event.

Check out these clips if you want to see video of the best stuff:
Highlight Reel and Personal Reflections
2019 Alberta Storm Season Recap

There are numerous considerations that go into determining the value of a given chase, including the rarity of what is seen, storm aesthetics, the amount of time spent taking in those moments, and those you share it with, to name a few. Here are my top 10 chases of 2019, with only one photo from each event selected to represent the day!

#10: Spruce View, AB - July 31. This cyclic supercell had some promising moments, with strong low level rotation in its best cycle. This beefy meso was also one of the better ones of the numerous I saw this summer along the foothills. I'm surprised this one didn't produce a tornado. A weak spinup did occur later in the evening, even though I couldn't see the ground circulation from my location. 

#9: Rainier, AB - July 7. This day over-performed. I began along the Porcupines west of Nanton and tracked it due east, encountering tennis ball hail and a large tornado west of Lomond. One of the best things about this storm was that it tracked through my favourite chase terrain in Alberta - Vulcan County. Open skies, rolling terrain, pristine cropland, and a lack of power poles along many grid roads. 

#8: Dogpound, AB - June 18. Similar to July 21, 2015, but better. All the barber poles you could eat rolled off the foothills NW of Calgary that evening, lined up one after the other. I documented 5 supercells that day, beginning near Eden Valley in the afternoon, and ending near Didsbury. 

#7: Crossfield, AB - July 14. This was a special day, because not only did the storm pop right in our target, but we watched it form from the initial cumuli to the moment it produced a tornado, and beyond. It was really nice sharing that moment with friends. I share this photo because this was really cool to behold - a narrow swath through maturing barley and wheat looked amazing from the air, revealing the snaky tornado track toward our viewing location to the southeast. 

#6: McCook, NE - May 17. We targeted this storm for days, so it was satisfying to see it go. One of the most photogenic tornadoes I've witnessed. 

#5: Carmangay, AB - July 18. I'm glad I told my buddy Glen to go check out the boundary in southern Alberta, as I had a mandatory dance rehearsal for our big Salsa performance at Festival in Calgary, causing me to be late to the party by about an hour. Of course, I was miffed. However, while documenting the aftermath of the tornado, we were able to rescue a kitten from under some sketchy debris and reunite it with a little boy who thought it was a goner. That, and the successful dance performance later made the day more than worth it. 

#4: Alder Flats, AB - July 23. There are a few days each season that really ring the wow meter, and this was one of them. To date, I have never quite seen anything else quite like this. You can almost get a sense of the vacuum-like motion in the storm here even in the still photo - a scene that was impeccably timed and lit by the setting sun. Even though the clouds visually appear to be screaming, it was dead silent aside from the concerned cattle that were bellowing out in the field.

#3: Follett, TX to Laverne, OK - May 23. We thought we had missed the boat on this day, as a large wedge occurred near Canadian on an earlier cycle that was seen by a few chasers to our west. However, it made sense to get ahead of it to see if it would go again, and that it did. Before dark, it became a prolific, long-track tornado producer that dropped more tornadoes of all shapes and sizes than we could accurately count. 

#2: Altus, OK - May 8. This was a "day after the day" chase, with low-topped storms firing in crisp, dry mid and upper levels. At sunset, this made for wonderful scenes - especially after we stumbled upon the Navajo Mountains of southwest Oklahoma. It took Jo and I a long time to pick our jaws up off the fields after seeing this structure. 

#1: Val Marie, SK - June 27. No, not a tornado. We made the decision stick ahead of this linear MCS as it charged east across far southern Saskatchewan at a blistering pace, and boy did it pay. A thick, stratified shelf that looked like it was chiseled out of marble atop marvellous foreground...what more could you ask for?

What were your top chases this year?

Storm Damage Documentation on the Prairies - Crossfield, Eston, and Carmangay

It has been a very active summer in the prairies, and we aren't done yet. At the time of writing on July 21, Alberta has already surpassed its annual average of 15.4 tornadoes based on the 1980-2009 climatology, which may have already been skewed a little high compared with recent years based on the active 80s.

Here are two tornado events in Alberta and one straight-line wind event in Saskatchewan that occurred in mid-July.

Crossfield, AB - July 14

A classic central Alberta severe weather day was expected on this day, with the focus of severe weather in Alberta expected through "hail alley" - just north of Calgary. A group of us sat just south of Crossfield, and watched as thunderstorms initiated early along the foothills to the west during noon hour. These messy-looking storms would generate an outflow boundary that would drift east toward the QE2 corridor, and become somewhat restrained by large-scale southeasterly flow. Rapid cumulus development ensued, with a line of towering cumuli sitting atop the low level convergence axis - and it didn't take long before we spotted a couple of vorticity funnels along the base. Further north, inflow features began streaming into an increasingly dominant updraft base, with a small notch developing to its west. We repositioned a few kilometres north, before a large funnel appeared in the notch, at the occlusion of a wrapping rear-flank downdraft. It wasn't long before a tornado spun up a couple of miles to our NNW, which wasn't fully condensed - but was associated with a dust whirl at the surface. It quickly became obscured in the rain, but continued for some time. The parent storm fought its outflow as it tracked east, but was the most prolific vorticity funnel producer I've ever witnessed, with several funnels sometimes occurring simultaneously along the shelf generated by the gust front.

The Crossfield tornado. Storm structure reveals it was mesocyclonic, despite numerous other nonmesocyclonic funnels occurring with the storm. 

Based on the damage path, the tornado cut a swath mainly through maturing wheat and barley crops, from NW to SE, beginning at 2:09PM MDT. To this day, it maintains its preliminary EF0 rating. However, damage suggests it could have been slightly more intense in my opinion (EF1), due to a holiday trailer being dragged and thrown 87m (determined by GPS) uphill to the southeast. A lack of damage indicators for vehicles makes an estimate of tornado intensity trickier in this case. The tornado spun up essentially right in the backyard of someone's property, where it sucked a horse trough dry of water, before impacting the RV and flattening a narrow swath of crops to the southeast. The crops would eventually stand up again (as observed in subsequent days), but a high translational speed compared with a relatively low rotational velocity likely resulted in the focused convergent pattern of crop material that was impressive to see firsthand. 

Apparently toilets are well-bolted. They always seem to survive!

Gouge marks are evident where the trailer scraped along the ground, before being deposited in the opposite ditch.

Very impressive track as seen from the air. The track width was no more than 20-30m. 

A close-up of the convergent pattern in bearded wheat.

Here is a link to a story I made for this tornado. 

Eston, SK - July 14

On the same day as the Crossfield tornado, other storms occurred further east across SE Alberta and into Saskatchewan. After abandoning the original Crossfield storm, we tracked another hailer south of Oyen, before noting explosive development of another storm to our east near Eatonia in SW Saskatchewan. This storm would go on to clobber the town of Eston, with street flooding, wind-driven hail that damaged siding, roofs, cars, and crops; and intense straight-line winds that caused significant damage particularly on the SW corner of town.

The storm as seen from the west that would go on to impact the town of Eston. Atom bomb vibes. 

Some folks in town thought a tornado had come through due to how intense the winds were. Others were okay with the official designation of straight-line winds, which have been called "plough winds". In my opinion, the damage incurred suggests at least EF1 intensity (135-175km/h) wind gusts. One resident showed me a video of the storm structure before it impacted the town, which revealed a descending precipitation bomb characteristic of an incipient downburst - and no evidence of funnel clouds. The consistent and widespread west-to-east damage also suggests it was a downburst - though I couldn't determine if it exceeded the scale of the designation of a microburst (damage over a width of <4km). Of note, a hangar at the airport was completely destroyed, with debris being thrown several hundred metres to the east. A 60 foot steel-trussed light tower also bent over at the base, and a roof ripped off one home and slammed into an exterior wall of the next, injuring a woman who was lying in bed at the time (dislocated shoulder). Most impressively was the 2x6 chunk of roof trussing that impaled a home two doors down, protruding into the living room. 

The home with the roof ripped off. 

60 foot metal-trussed tower tipped over

Large grain bins (empty at this time of year) take flight to the east, just west of Eston.

Hail up to the size of golf balls stripped homes of vinyl siding. One home had damage almost right up to the eaves despite having a large overhang, suggesting the hail was coming in almost sideways.

An embedded 2x6. This image sticks with me!

Here is a link to a story I did on this event. 

Carmangay, AB - July 18

Vulcan County has been a lot more active this year than in recent times. For a storm chaser, it is a dream to chase here owing to a decent road network amid rolling terrain, pristine cropland, and excellent visibility. This tornado (like Pine Lake, Three Hills, Jenner 2017, etc) occurred along a boundary in a classic Alberta tornado environment. These kinds of days often don't scream tornado in the days leading up to it, as they are usually post-frontal setups on the cold side of a trough, with messy low level shear profiles and less instability than before the trough came through. However, there is often usually enough residual moisture pooling into the north side of the QS boundary/front, which is impinged by strong, dry W/SW flow across southern Alberta - which can feature an impressive moisture gradient along with a wind shift and associated convergence that supports thunderstorm initiation. Ample instability results on the cool side of the boundary for severe storms amid deep layer shear favourable for updraft rotation (despite the messy low level shear profile) along the cyclonic shear side of the jet, which can support low-topped supercells with storm motions along the front, providing a steady stream of streamwise vorticity for strong low level mesocyclones. The probability of tornadogenesis may also increase in this environment owing to the presence of plentiful environmental low level vertical vorticity along the wind shift line. 

Tornado occurred between 515-530PM MDT. Notice the wind shift, the strong moisture gradient, and the deviant motion to the SE of the parent tornado thunderstorm when updraft rotation was strongest.

Visible satellite and radar trends indicate that the storm itself developed rapidly, as an outflow boundary from a decaying storm to the north collided with the in situ boundary. 

Meteorogram for a nearby ag station reveal the strong, dry westerly flow that preceded the storm. 

The tornado spun up about 17km east of Carmangay in a field just NW of a residence that would become heavily impacted by it - particularly on the northern edge of the property. The home itself sustained some damage, including broken windows, impaling of branches into the home, and some stripped siding and roofing material along with extensive tree damage in the yard. Just north of the home, a well-constructed shop building was destroyed, with a car jack stand inside shifting 10 feet. Anchor bolts were ripped out of the concrete cribbing, and heavy equipment was tossed into the field - including a bale stacker that was thrown 200 metres. At the time of writing, the tornado was given a preliminary rating of EF1 - however, once again in my opinion, some of the damage (that may lack damage indicators for surveyors) suggests EF2 intensity (180-220km/h), and had an estimated (by me) track of over 10km to the SE. A couch cushion was found laying in a field of flattened peas almost 4 kilometres SE, with insulation observed almost 10 kilometres SE. The tornado would thread the needle through wind turbines at the same time that straight-line wind damage was being reported a few kilometres to the west. 

An overview of the property impacted by the tornado. 

Branches impaled into the side of a home, likely from a tree bough being forcefully thrown at it.

The branch coming into the living room.

The destroyed shop. 

Damage that occurred to a barn at the Carmangay Colony to the west. 

The most memorable piece to this story for us however, was the seemingly miraculous survival of some of the animals on the property. As we were doing the survey, we heard something crying from beneath the heap of rubble that had been the shop. We looked inside, and found that it was a tiny Calico kitten. After some careful maneuvers, we were able to retrieve it from the rubble and return it to his owner - a happy little boy. Apparently there had been two, but until that point only one had been accounted for, and all hope for the second was lost. 

Here is "Calico" - who may have used up one of her nine lives. 

The family dog Belle was also seen clawing at the ground outside the basement window as she attempted to avoid getting carried away by the tornado - but to no avail. She got carried away, but somehow returned a while later. 

Belle standing near the wreckage of the shop.

And finally, as we were calculating the distance that the bale stacker was thrown, a little calf came running up behind us crying. Apparently, four calves on the property had their bottle feeder destroyed near the shop, and were looking for food. 

 Here is a link to the kitten rescue, is a link to more of what happened on the property, and here is a link to video of the tornado shot by Sara Banman - the neighbour immediately to the south. She ran for cover after finishing filming.