Tom Thomson and the 1915 May Two-Four Weekend

Something very rare happened on the "May Two-Four Weekend" in 1915. A volcano that had been sleeping for about 27,000 years suddenly woke up at about 4:00 pm Saturday afternoon. Lassen Peak in northern California produced a violent explosion that ejected rock and pumice high into the atmosphere. This explosion was the most powerful in a series of eruptions from 1914 through 1917.

On May 22, 1915, an explosive eruption at Lassen Peak, California, the southernmost active volcano in the Cascade Range, devastated nearby areas and rained volcanic ash as far away as 300 km to the east. 

Tom Thomson was staying at Mowat Lodge on Canoe Lake, busy painting before the black flies emerged and waiting for guiding and fishing to occupy his time. Tom would have been oblivious to how a faraway volcano might influence his choice of pigments. Thankfully, Tom painted what he saw.  

World War One, the so-called first "Great War" was still raging in Europe. Tom's artist friends had dispersed to participate in that conflict in one way or another. Sadly, they were unable to accompany him on his last artistic adventures which ended prematurely with his death in July of 1917. On the positive side, Thomson was finding his own, unique artist voice and creating magnificent work.

Three years later, in the spring of 1918 Lawren Harris and J.E.H. MacDonald faced a virtually impossible task to sort through the two or three hundred panels that Tom had created in their absence. The undocumented panels were stacked high in Thomson's Shack. 

His friends attempted to sort through the paintings selecting what they felt were the best works to establish Tom's legacy. The Estate Stamp applied to the front and back of the panels would authenticate his art. Tom only signed the panels when asked to do so. He certainly never bothered to put names on his paintings. In fact, Tom rarely made any mention of the inspiration for his paintings leaving the art to speak for itself.  As a result, this was a gargantuan but essential task for his friends. Many of Tom's originals had already dispersed to the wind to anyone who took a passing appreciation for his brush strokes.  

The estate stamp typically in the lower right often resulted in some paint eventually flaking off. The panels salvaged from The Shack and organized in the Studio building all display the stamp.

Harris and MacDonald certainly were enthralled with Tom's art but had little or no first-hand knowledge of the story behind them. They had to rely on their own devices to create plausible titles based on the subject matter and possible locations. MacDonald had never been to Algonquin. Well-intentioned mistakes were made. These are easily forgiven. Those errors still remain in the Tom Thomson Catalogue Raisonné but there is hope!

Using science and topographical maps, we can correct those mistakes - something that I have been doing since the mid-1980s. As an example, it is interesting that more than a century later, we can trace Tom's movements on the Victoria Day weekend of 1915 using only his art and a volcanic eruption in California. Please let me explain. 

From detailed research into Tom's movements, we can be fairly certain that Tom was at Canoe Lake on the weekend of May 24th, 1915. Tom was likely staying at Mowat Lodge but occasionally ventured to his favourite haunt on Hayhurst Point less than a kilometre to the east. 

Thomson Travels 1915

• March 13 – April 10: Ontario Society of Artists Forty-third Annual Exhibition, Toronto. Thomson exhibits Northern River, Split Rock and Georgian Bay Pines. Northern River is bought by the National Gallery of Canada for $500. His address is given as Studio Building, Severn Street.
• Mid-March: Arrives in Algonquin Park, via Huntsville, where he stays at the home of Winifred Trainor for two days; he travels to Tea Lake and Big Cauchon Lake; in the Kearney area, he stays at McCann’s Halfway House.
• A.Y. Jackson had returned to Quebec, evidenced by a letter to his sister Kate, dated April 18th, 1915, which he sent from Emileville Quebec. In it, he discusses his intention to join the army. His attestation papers show that he enlisted on June 14, 1915.
• April 28 – May 19: Thomson and George Rowe guide the Johnston Brothers of Pittsburgh, Pennsylvania to Pine River; they travel to Tea Lake. On their return, Thomson and Rowe travel to Big Bear Lake.
• May 24 Weekend...
• July 17: Assists H.A. Callighen in bringing tourists from Joe Lake Station to Smoke Lake by canoe.

A case can be made that links four of the 1915 paintings using colours, the volcano, the parade of weather across Canoe Lake and science.

I propose that these four sequential paintings recorded every sunrise and sunset at Canoe Lake starting on the evening of Saturday, May 22nd, 1915 - the day that Lassen Peak erupted. The potential paintings are included in above. Brief explanations follow. Detailed analysis and diagnosis of each painting can be found in the linked blogs.  Please ignore the official names of the artwork which identify them all as sunsets - two of the four were certainly sunrises. 

Sunset, Saturday May 22nd, 1915

On the late afternoon of Saturday, May 22nd, Thomson was visiting his favourite site on Hayhurst Point. He recorded the backlit clouds looking westerly at sunset in Painting 1.  A spring weather system was approaching. The details are explained in Tom Thomson's Sunset Sky, Summer 1915. Harris and MacDonald were correct in identifying this as a sunset. I feel they missed the mark by identifying the season as summer perhaps because the name "Sunset, Spring" had already been used in  Painting 2. Tom typically spent his summer guiding and fishing. He did not paint much in the summer because of pesky biting insects. The clouds are also not overly convective as one would expect in mid-summer.  

Sunrise, Sunday May 23rd, 1915

At dawn on Sunday, May 23rd, Tom was on the shore in front of Mowat Lodge looking easterly to observe strong sunrise colours in the backlit clouds. The unusual sunrise colours would have penetrated Tom's room on the second floor of Mowat Lodge. Tom must have been compelled to grab his oils and make a weather observation. For a detailed analysis see Tom Thomson's Sunset Sky, Spring 1915. The terrain features of the eastern shore of Canoe Lake as well as those recorded in other Thomson paintings confirm the easterly view. The clouds also confirm that Tom was observing the wake of a cold front. The weather system that had been approaching at sunset on Saturday had crossed Canoe Lake overnight probably bringing precipitation overnight. 

Harris and MacDonald would have incorrectly interpreted the strong colours as a sunset sky unaware that the higher level volcanic aerosols transported by the jet stream had already arrived over Canoe Lake.

Tome would have been interested in the strong colours exhibited in the sky all day Sunday. There could be other paintings to include in this sequence. We can be certain that Tom paddled over to his Hayhurst Point haunt to observe the vivid sunset colours looking west. 

Sunset, Sunday May 23rd, 1915

The details of the analysis and diagnosis can be found in Tom Thomson's "Sunset" 1915. Harris and MacDonald called Painting 3 "Sunset" from the summer of 1915. They were certainly correct about the sunset part but the season was spring right after the volcanic eruption. Matching the terrain features confirms that Tom was looking westerly across Canoe Lake. The jet stream had already delivered the next low-pressure system in the parade of weather. This time the strong winds also brought thicker concentrations of volcanic aerosols dramatically influencing the sunset colours. Tom painted exactly what he saw!

Finally, Tom awoke on Monday, May 24th, 1915 to a brilliant sunrise streaming in his window of Mowat Lodge. Terrain matching again confirms his easterly viewing angle. 

Sunrise, Monday May 24th, 1915

The weather system that arrived at sunset on Sunday had passed east of Mowat. Tom was observing the sunrise light scattered from the underside of the cirrus and altocumulus cloud found in the "hang back - comma head" of the storm. The details of the analysis are recorded in Tom Thomson's Sunset, Summer 1915. Harris and MacDonald miss-named Painting 4 as "Sunset, Summer 1915" reusing the same name as applied to Painting 3. Understandably, the unusual sunrise colours tricked them again. They were also running out of unique names to employ. 

Tom must have been aware that something very unusual was happening in the atmosphere. This lends some rationale for Tom to diligently observe the increasingly spectacular colours in a series of paintings. Paintings number 1 and 3 in the above series are the only actual sunsets looking westward. 

Painting 1 Saturday sunset left -Painting 2 Sunday sunset about 30 hours after the eruption right

Painting 1 was completed just a couple of hours after the eruption well before the arrival of the volcanic aerosols. Painting 3 was completed with the arrival of the first high concentration of volcanic aerosols. The initial concentrations of aerosols can be very high behind the deformation zone of the airflow that delivers those particulates. Tom must have been amazed at the vivid sunset colours!

Paintings 2 and 4 repeated below are truly sunrises looking eastward from Mowat. The colours increased in chroma between Sunday morning on the left and Monday morning on the right. 

The progression of cloud types and structures is consistent with two separate weather systems that crossed Canoe Lake over the May Victoria Day weekend. Rain likely fell both Saturday and Sunday nights. 

In any event, Sunday supper on the Queen Victoria Holiday weekend would have been memorable - not only because of the "fireworks" in the sky. Annie Fraser, Shannon's wife was well known for her fine meals and baking at Mowat Lodge. (Note: May 24, Queen Victoria's birthday, was declared a holiday by the Legislature of the Province of Canada in 1845. After Confederation, Queen Victoria's birthday was celebrated every year on May 24 unless that date was a Sunday, in which case a proclamation was issued providing for the celebration on May 25.) The Great War was still raging in Europe and patriotic feelings would have been high. 

           Tom Thomson circa 1905-1910                 

To really appreciate Tom Thomson, it is important to place his art within the context of the times in addition to the science and the weather. 

What motivated Tom to record these weather observations? Tom must have been shocked to see the colours of the sunrise reaching into his bedroom window. I can imagine Tom grabbing his paint box and rushing out to the shore of Canoe Lake to chase the sunrise light before it disappeared. Tom was also a morning person... let's get going with the sun. Rise and shine.

Tom would have been eagerly waiting for the display of colours that the sunsets would deliver. That is why artists paint... we all chase the light in amazement at the beauty of nature ... and the weather. 

Tom might not have understood all of the science and would certainly not have known that Lassen's Peak had just exploded - but he was truthful to what he saw. In that way, the science he recorded must also be accurate. 

Warmest regards and keep your paddle in the water,

Phil Chadwick

PS: Tom Thomson Was A Weatherman - Summary As of Now contains all of the entries to date. 

PSS: If one searches Tom Thomson's Catalogue Raisonné  for "sunrise" only one painting shows up. If one searches for "sunset" 25 works are produced. Some of those sunsets are actually sunrises as we have demonstrated. Of course, it would have been helpful if Tom had left a few hints. 

Tom Thomson's "Smoke Lake" 1912

In 1976, when I graduated from Queens in Nuclear Physics, I was not aware of the friends that I would make forty years later thanks to Tom Thomson. It turned out that several of my future Thomson friends were also involved in nuclear physics. Except for a twist of fate, I was also destined to go to Chalk River to study and work in the Nuclear Industry. Those friends would have been encountered that much sooner in Deep River, and while paddling the Petawawa and the Dumoine Rivers.  One can only ride one horse at a time, and meteorology came along first, so I saddled up. There can be no looking back, but I often wonder.. Giddyup...

Smoke Lake
Alternate title: Smoke Lake, Algonquin Lake Spring 1912
Oil on paperboard (Birchmore board)
7 x 9 15/16 in. (17.8 x 25.2 cm) 
Tom's Paint Box Size

Meanwhile, in July of 1977, Jim and Sue Waddington began a 36-year journey of discovery that culminated with "In the Footsteps of the Group of Seven" in 2013. Jim even attended the same high school in Brockville, graduating from BCIVS in 1959.  Jim became a professor of physics at McMaster University, specializing in nuclear physics. Jim even married his high school sweetheart, as did I. 

My prized, autographed copy of Jim and Sue Waddington's book

Diana and Bob McElroy began their investigations into the painting places of Tom Thomson in the 1980s. Bob McElroy also has a strong background in physics. Both Diana and Bob worked at Chalk River. They enjoy a large and significant web presence detailing the painting places of Tom Thomson. I found these sites invaluable when working on the "Tom Thomson Was A Weatherman" blogs. 

I am fortunate to count Jim and Sue Waddington, the authors of "In the Footsteps" and Diana and Bob McElroy as friends. We share a similar life stories. They have contributed to several of the posts comprising "Tom". In fact, our ongoing friendship leads to this story.

Jim writes: "Sue read somewhere that Tom Thomson, working as a guide, took people to Molly's Island in Smoke Lake. So that was as good an excuse as needed to go for a paddle. The wind came up, and the skies darkened. The island is small. I remember a small sandy beach on the north side. We crossed the island, took a photo, retreated to the canoe, and got soaked."

The Waddington photo was taken looking south from the south shore of Molly's Island

The very best way to start with a Thomson post is with the painting location. Using that information, the direction of view is well established from the get-go. I am only left with the earth sciences to unravel. 

Comparing the Waddington photo with Tom's "Smoke Lake" was an interesting exercise that few will ever bother to do. Tom certainly was unconcerned, being in possession of his "Artistic Licence" - as am I. He chopped 16% from the width of the horizon to make his subject fit the small plein air panel. Tom judiciously removed the uninteresting flat portion of the distant ridge line. The following graphic guides you through the steps I took to deduce that cryptic number. 

2.6 cm chopped out of the flat ridge line in the Waddington photo is 16% of the 16.5 cm wide horizon.

My long-time Thomson friend and expert Daian McElroy remarked:

"How fortunate that the Waddingtons were in the right spot when the weather was so appropriate.  And I found your examination of the details of how Tom tweaked the landscape to be very interesting.  Despite those changes, the sketch still conveys the essential landscape - that's the location all right, without a doubt."

The match to the terrain with the described adjustments is indeed almost exact. Tom also frequently exaggerates the vertical extent of the terrain. He refrained from making significant changes to the heights in "Smoke Lake". The subject of this painting was the weather and not the hills. 

As noted, the weather in the Waddington photo was a close match to what Tom painted! 

Looking south from Molly's Island across the south basin of Smoke Lake

The winds were strong southwesterly on the afternoon that Tom painted "Smoke Lake". Using the Beaufort Wind Scale and matching the waves and whitecaps to the descriptions, the winds are estimated to be 20 to 25 knots (37-46 kph) when Tom was painting. The fetch across Smoke Lake is also an important factor, and the winds could have easily been stronger in a more exposed location. 

• 17-21 knots- Fresh Breeze-  Moderate waves, taking a more pronounced long form; many white horses are formed. Small trees in leaf begin to sway; crested wavelets form on inland waters.
• 22-27 knots- Strong Breeze- Large waves begin to form; the white foam crests are more extensive everywhere. Large branches in motion; whistling heard in telegraph wires; umbrellas used with difficulty.

Note that the waves were much smaller in the lee of the distant shore, so the strong wind had to be mainly from the south. Further, the shape of the cumulus elements (the white arc in the above graphic) comprising the flanking line revealed that the winds at cloud level were southwesterly. 

The convective cloud was quite likely a cumulonimbus - simply a thunderstorm. Tom included the rear edge of the flanking line. That cloud was front lit, indicating that the sun was in the western sky - it was afternoon. Thunderstorms typically require significant daytime heating before they fire up, so they are more unlikely in the morning. The cloud was tall above the very dark base, which is characteristic of cumulonimbus. 

SCUD is meteorological slang for "Scattered Cumulus Under Deck". The "deck" referred to is the base of the cumulonimbus cloud, which is the lifted condensation level (LCL) for the air mass. Daytime heating of the land warms adjacent air parcels, which rise buoyantly to saturation at the LCL. 

SCUD are twisted shreds of cloud lifted from the ground by the turbulent winds. The moist surface air parcels are turbulently stirred and lifted to saturation. These air parcels saturate to become clouds "under the deck" if the ground and turbulent air parcels are additionally moist from any preceding rain.  

I used the conceptual model for a supercellular thunderstorm as a worst-case scenario. There is no absolutely conclusive evidence in Tom's painting that the convection was even a thunderstorm. Tom did not include lightning this time on his panel. The flanking line is characteristic of the significant wind shear required to create both multi-cell type cumulonimbus and supercells.  The following photo depicts a multicell thunderstorm looking from the south while Tom was on the northwest flank of the convection. 

Jim Waddington writes:

 "Many years ago, my father had a book about instant weather forecasting. I  often use the ideas while on a trip. The only trick that I remember was that dark skies with small, low, fast-moving black clouds means 'rain within five minutes'. We were about to get wet but so was Tom."

"Instant weather forecasting" is about learning from the lines in the sky... see "Lines in the Sky and the Meaning of Life" for more details. However, meteorology is typically much more complex than what can be viewed from your immediate location. Weather is always lurking just beyond the horizon. I advise that a meteorologist accompany every canoe trip... 

The trick that Jim remembered, "small, low, fast-moving black clouds" refers to SCUD  clouds. Depending on the illumination, the optically very thick SCUD clouds can be dark (backlit) or white (frontlit) as in Tom's weather observation above. The SCUD indicate that it has rained recently nearby and that moisture has been lifted to saturation by strong and turbulent winds. The fact that the clouds can be seen to be moving quickly tells us that they are nearby and thus close to the ground. Depending on the location of the convection, more showers could be just minutes upstream. This is a good trick.

I also asked my colleague Johnny Lade to have a look at this painting as if he were making a weather observation. Known to his students as "Johnny Met", he has a lifetime of experience observing the actual weather. Johnny nailed this observation since Thomson painted exactly what he saw.

"At first glance, I knew Tom had stopped a summer thunderstorm.

He painted, fast-moving Scud clouds, white caps on the lake, probably a wind shift in the down draft, bringing cooler temperatures, thunder and lightning, and heavy showers. Tops of the cloud would be into the tropopause, moving the cumulonimbus cloud at a fast speed, so quickly that in ten or fifteen minutes, the sun would return. A fresh and cooler air from thirty thousand feet and the smell of ozone.

I worked many thunderstorms in my weather career from daytime heating afternoon summer thunderstorms to the fast moving line ahead of a crashing cold front and the sneaky warm front thunderstorms causing lots of noise in the middle of the night. 

Most of my career were postings at airports so passing thunderstorms put a crimp in arrivals and departures with sudden wind shifts: with a head wind suddenly becoming a tail wind needing a longer runway on landing, and small aircraft not tied down on the ramp."

Many thanks to my friend Johnny Lade. His observation rings true, breathes life into Tom's painting, and adds another dimension to the story. Thomson loved painting thunderstorms!

Tom typically reserved his summers for fishing. The biting bugs discouraged staying still in one place for too long, which rules out painting. The potential to fish and be reimbursed while doing so is called "guiding". Tom was all in for that lucrative enterprise, as art did not really pay. 

Molly's Island on Smoke Lake would have been a perfect fishing and camping destination. An interesting 6-kilometre paddle from Mowat Lodge was all it took. The numerous shoals around and just south of the island are still readily apparent on Google Earth and probably attracted great schools of fish in Tom's day, well before the pressure on the fishery increased to current levels. 

"Smoke Lake" is certainly one of Tom's early works and likely correctly dated as 1912. Tom did not even sign his later plein air works. If so, this painting of a thunderstorm was completed on Thomson's first trip to Algonquin in May of that year. Tom was 34 years old and accompanied by his Grip coworker Harry B. Jackson.

Algonquin Park Ranger Mark Robinson met the Thomson and Jackson at the Joe Lake Train Station on the Saturday evening after a day of patrolling the Burnt Island Lake area. 

Later, Ranger Bud Callighen, met two individuals camped near Tea Lake Dam. Callighen did not identify the men, but the descriptions in his diary matched Thomson and Jackson. It was widely known that they had camped at the easily accessible Tea Lake Dam south-west of Canoe Lake. Callighen noted "two men camped at (Tea Lake Dam)" because most park visitors hired a local guide to show them around in 1912. 

H. B. Jackson's  wrote a Letter to Blodwen Davies dated May 5, 1931 describing Thomson's Algonquin trip.

"I am quite sure it was Tom's first visit to Algonquin Park. Tom MacLean a Toronto artist who was located with us at the Grip, gave us a letter of introduction to the elder Mr. Bartlett, who was supt. of the Park at that time:

MacLean (sic) told us of the beauty & fine fishing in that region & Tom & I thought we would try it. […]

Tom did get his painting outfit in the spring of 1912 & used it on our trip & afterwards with Broadhead; While we were together he did very little serious sketching, making a few notes, sky lines & color effects." 

H.B. Jackson completed the accompanying portrait of Thomson during that first visit to Algonquin.

A few months later, Jackson would write about the camping experience without a guide in the Editorial Section of The Toronto Sunday World on August 11, 1912 (see the accompanying article).

The above text is not clearly legible, but the hunt is on to find a transcribed version. 

Supercellular thunderstorms are fairly common in Algonquin in May due to geographical and terrain influences. I watched for such situations as a severe weather meteorologist! The brown hues Thomson selected to depict his thunderstorm from Molly's Island are characteristic of severe convection. Such a storm would have certainly caught Tom's attention, even though H.B. Jackson remarks that "he did very little serious sketching". All of the puzzle pieces fit together quite nicely. 

Inscription recto: 

• l.r., Tom Thomson 

Inscription verso: 

• t., in graphite, Smoke Lake / Algonquin Park; 
• c., in graphite, ca. 1912; 
• b.r., 5 (circled) National Gallery of Canada, Ottawa (4676) 

  

  The edges of Tom's panel show how it was
  slid into and out of his paint box.
  
  

Provenance:

• Dr. J.M. MacCallum, Toronto, c. 1913 
• James MacCallum, Toronto, before 1940 
• National Gallery of Canada, Ottawa (4676). Purchased from James MacCallum, Toronto, 1946

That's the complete story behind Tom Thomson's "Smoke Lake". His painting was really another skyscape that focused on the characteristic shapes of clouds and the weather. It was not about the lake at all. 

I wish to thank my fellow physicists for their investigative diligence and for tracking the painting places of Tom Thomson and the Group of Seven. They have filled in a large number of blank pages in the art history of Canada. Kudos to the Waddingtons and the McElroys! Thank you... We are all in this together!

Now on to more of Tom's art and meteorology in the next Blog. 

Warmest regards and keep your paddle in the water,

Phil Chadwick, Tom Thomson Post TT-199

PS: Tom Thomson Was A Weatherman - Summary As of Now contains all of the entries to date.

Tom Thomson's "The Hill in Autumn" 1914

My first diagnosis of "The Hill in Autumn" really troubled me! Some subtle inconsistencies bothered me enough that the story did not get published in the first go-round. The puzzle pieces did not fit together as nicely as they should. Was Tom looking east or west? Were the coniferous trees in the centre of the painting in shadow (looking easterly), or were there no deciduous trees there because of soil conditions?

The illumination of the scene was sufficient to bring the colours out of the forest. The sun had to be a least a bit on Tom's back or at least overhead. The clouds were no problem, but I needed to be certain of the direction of view! Was that storm coming or going? Let me explain... please. 

"The Hill in Autumn" Fall 1914
Oil on composite wood-pulp board
8 7/16 x 10 1/2 in. (21.5 x 26.7 cm)
Tom's paint box size, 1914.72

My friends Jim and Sue came to the rescue again! The "paddle in the water explorations" of the Waddingtons were instrumental in correctly solving the riddle of Tom Thomson's "The Hill in Autumn" from 1914. We must also acknowledge Tom Thomson for painting exactly what he saw. Tom did not make anything up! 

The Waddington image from Broncho Island on the left with "The Hill in Autumn" to the right. 

A picture is indeed worth a thousand words. Tom, along with pretty much every artist I know, will distort the subject to better fit the size of the painting surface that they have available. Tom scrunched the horizontal dimensions, but the details remain unmistakable. 

Jim wrote: "It was quite windy, so I think we tried to land on the north-western end of Broncho Island to take the photo. That was difficult too." 

The photo was taken looking west. The topography matching Tom's painting was unmistakable. 

Jim writes further: "I have since learned from the Voyageur Outfitting site about their island retreat. The Island was once a 'camp' of Tom Wattie, who was an Algonquin Park ranger from 1900-1931. Tom Thomson was also a park ranger at this time and became good friends with Wattie, visiting him often at his camp, now known as the Algonquin Island Retreat."

Bronco Island is on Kawawaymog  Lake, which was formerly known as Round Lake. 

Jim and Sue also observe: "Thomson probably wasn't in the middle of the lake like us but was on one of the islands, presumably Wattie's".

With the viewing direction firmly established, I could make progress on the meteorology in Tom's painting. The skyline was at the lower third of the small panel, so the subject that caught Tom's attention was most certainly the weather. 

It was a windy day as well when Tom made his weather observation. Mares' tail cirrus was overhead in an azure sky. Recall that backlit cirrus is not dark in its centre like more opaque clouds. Cirrus ice crystals are just not present in sufficient density to block the sunlight. 

The shape of the cirrus cloud elements is all we need to establish both the average wind and the deviations from that mean, which sculpt those intricate patterns. It is easiest to just witness the cloud drift across the sky to establish the average wind. The entire mass of moisture simply moves along with the mean flow. For example, I was able to easily follow the motion of the mares' tails depicted in the following graphic, so I knew the direction of the average wind. That is not possible with a still image, but the shape crafted by the relative winds can still reveal the mean. 

The cloud shape revealed that the average wind at cloud level would have been from right to left, as depicted in the painting and in the actual clouds I photographed. Thus, the upper winds were from the north since Tom was looking toward the west (thanks to Jim and Sue). The following graphic details these deductions and will serve as an introduction to cloud watching. Actual mares' tail cirrus are included along with Tom's interpretation of what he witnessed. 

See "A Jet Streak with a Paddle" for an explanation of the atmospheric frame of reference.

The following graphic applies the above concepts to the still images of mares' tails in Tom's "The Hill in Autumn". Remember that clouds are three-dimensional and exist through a depth in the atmospheric ocean, although we only witness planar views, especially in the painting. For example, the green col symbol at the leading edge of the cirrus is probably at a higher level than the swirls sketched. The col and lines of the deformation zone conceptual model must be continuous in the view of the processes on a piece of paper. 

Try to visualize the swirls as three-dimensional vortices tilted forward with the strong winds along. The col at the nose of the cirrus would be as sketched in the graphic. Any ice crystals wafting groundward would be caught in the vortices that flank the local wind maximum embedded within the mean flow. These processes neatly explain the swallow-like appearance of the cirrus uncinus, which is what really attracted Tom's attention in the first place! 

My COMET friends in Boulder could manufacture a wonderful animation of this dynamic structure and make it come alive! For now, please try to play that image in your mind using your Coriolis hand. My efforts to explain this in the weather centre were typically unsuccessful, but I never give up. Also see "A Closer Look at Lines in the Sky" which is one of several explanations of deformation zones and the important role that they play in understanding moisture patterns in any fluid.

I was in the Studio and decided to manufacture a three-dimensional representation of the planar view of mares' tail cirrus. In the image, using my Studio step stool, the wind increases with height from the floor through steps one and two. The strongest wind is in the direction of my mahl stick (circa 1966) positioned at the very top of the stool. 

The wind spins the paper towel rolls in the sense indicated. The "cloudy" white roll to the left (looking downstream) of the local wind maximum spins cyclonically (the red arrow) - the thumb of your Coriolis hand will be pointing up.  The "blue sky" roll to the right (looking downstream) of the local wind maximum spins anticyclonically (the blue arrow). Your Coriolis thumb will be pointing downward.

The wind is strongest at the level of the mahl stick, so both of these rotating vortices are tipped forward with the wind. The moisture is also advanced furthest downstream at this level, represented by the cushion at the tip of the mahl stick. 

Now visualize the ice crystals from the cirrus caught up in these vortices drifting toward the earth - gravity gets us all eventually! I draped the towel sheets to try to represent how that might look. 

The final visualization is a quasi-horizontal cross-section through the towels and mahl stick, integrating what one would see from the ground, seeing all of the different layers of the three-dimensional moisture. 

Now back to "The Hill in Autumn". The wind direction at the surface can be quite different from that revealed by the cirrus above 20,000 feet. In this case, though, we can be quite certain that the winds were brisk and chilly northwesterlies.  

The blue skies and clear visibility were characteristic of a ridge of high pressure over Tom. Air generally subsides ahead of a ridge, and the pressure at the ground rises with the fair weather.  That's why people have barometers on their walls. The air was dry, and there was not even a hint of cumulus clouds under the sunny skies. 

Winds are generally calm in a high-pressure centre. The wind speed inducing the waves that Tom painted would only be found in the anticyclonic flow ahead of the ridge or after the ridge had passed. The former is certainly the case in this situation as the cirrus is not a large deck of cirrostratus but rather isolated, thin mares' tails. Cold air advection is also much more likely to bring the momentum of stronger winds aloft descending to the surface. Recall the constant energy trajectories that air parcels follow, sloping downward to the ground as they head south. See "Isentropic Surfaces - Science and Art Merges" for more explanations and details. 

The other important part of this puzzle can be seen on the western horizon. Bands of rose-coloured cloud stretch along a deformation zone that encloses the warm conveyor belt of an approaching weather system. Tom painted bands of cirrostratus within gravity wave swells being stretched by the deforming flow. 

Like in the ocean, the atmospheric swells propagate outward from the source but are most significant in the same direction as the strong winds that generate them. Using the westerly nature of the jet stream and this fact would be enough to realize that Tom had to be looking toward the approaching storm. I felt that the swells in the cirrostratus might not be sufficient evidence, even though I was convinced. I can be pretty gullible. 

Separately, each puzzle piece described above cannot fully diagnose the weather pattern. However, the pieces can only fit together in one way to make meteorological sense. The following graphic summarizes how the mares' tail cirrus, strong northwesterly upper winds, brisk northwesterly surface winds and distant swells of cirrostratus must fit together. It may not be rocket science, but I still think the story is a blast. 

A similar parade of weather occurred on April 7th, 2025. The sky overhead Singleton included a few patches of mares' tail cirrus, which I watched to establish the northwesterly flow aloft in an earlier graphic. Some cirrostratus was low on the horizon but too subtle for an interesting picture. The sky changed dramatically in just an hour or two. The approaching storm was racing toward the east. The following graphic describes those lines in that sky. Weather is important. 

Here is that same view at noon the following day. Winter had returned to Singleton. The intensity and speed of the weather system could be inferred from those lines in the sky. I spend a lot of time looking up at the sky - time well wasted!

I consulted with my weather friend Johnny Lade.  John made the following excellent observations:

"I always look for the western horizon. Maybe from thirty years of doing weather observations and looking for a deformation zone. In my ground school teaching, I always told my students to notice trends. Always watch the weather on TV and feel the weather.  

So, in your description, the first day of a high is windy, too windy for my pilot friends to go up and do cross countries. The second day and into the third day will be fine before the strong westerlies develop. I have a barometer on the wall by the door in my house to follow trends.

I have favourite clouds. This painting has mare's tails and invading altocumulus! "

John and I spend a lot of time marveling at the weather. We are perpetual students and always happy within our natural laboratory. 

The "The Hill in Autumn" was another painting comprising the very tall stack of panels salvaged from Thomson's Shack in the spring of 1918. Harris and MacDonald enjoyed a relatively easy time naming this work. The painting depicted a prominent hill, and the deciduous trees were the colours witnessed in autumn. There was no need to discuss the clouds in the sky even though they were the subjects of Tom's weather observation. 

The determined investigations of Jim and Sue Waddington were essential to unravel the real story behind Tom Thomson's "The Hill in Autumn". The science comes to life when we can be certain that Tom was looking west while he painted. Thank you!

Inscription recto: 

• l.r., estate stamp Inscription verso: 
• c., estate stamp; 
• u.l., in graphite, AM; 
• u.l., in graphite, 8; 
• c., in graphite, 6A (or 46A); 
• below stamp, label, in graphite, The Hill in Autumn / 
• 1914-J and in ink, Dr. James MacCallum National Gallery of Canada, Ottawa 

This was another one of those panels that caught the eye of Tom's patron, Jim MacCallum. The good doctor must have made the acquisition when the panel surfaced during the sorting and naming process in the spring of 1918. 

Provenance:

• Estate of the artist 
• Dr. J.M. MacCallum, Toronto 
• National Gallery of Canada, Ottawa. Bequest of Dr. J.M. MacCallum, Toronto, 1944 

"The Hill in Autumn" as it would have
appeared in Tom's pochade box.

To really appreciate Tom Thomson, it is important to place his art within the context of the times, in addition to the science and the weather. The so-called Great War was raging in Europe and consuming the full attention of his friends. Meanwhile, Tom surrounded himself with the wonders of nature in Algonquin Park. 

In "The Hill in Autumn", Tom actually captured the swallow shapes of the tilted vortices associated with a local wind maximum in the upper atmosphere - cirrus uncinus. This was a skyscape painting. Paint on Tom!

For those interested in a bit more science, I also wrote about "Curly Hook Cirrus" in "Lines and Swirls Explained".  Also in "A Jet Streak with a Paddle" I explained why deformation zones parallel the wind in the entrance region of a local wind maximum. In sharp contrast, the deformation zones are perpendicular to those winds as they decrease downstream from the local wind maximum. These clouds can reveal a lot about the atmosphere. These discussions were a tough sell in the Weather Centre when the pressures of deadlines and workload precluded a more artistic investigation of the "why" behind the clouds.

Warmest regards and keep your paddle in the water,

Phil Chadwick, Tom Thomson Post TT-114

PS: Tom Thomson Was A Weatherman - Summary As of Now contains all of the entries to date. 

PSS: Should you wish to have Creative Scene Investigation applied to one of Thomson's works that I have not yet included in this Blog, please let me know. It may already be completed but not yet posted. In any event, I will move your request to the top of the list. If you made it this far, thanks for reading!