Tom Thomson's Sunset Sky, Summer 1915

One of the unspoken motivations for investigating the art of Tom Thomson is to encourage others to view nature and the weather as he did. A greater understanding of both leads to appreciation and perhaps respect. Conservation of the environment must certainly follow a thoughtful appreciation of nature. 

There are several very interesting aspects of meteorology that Tom included on this plein air panel. That is my motivation to include this work in the book although it was never included in the "Tom Thomson Was A Weatherman" presentation. That presentation would get much too long if everything was mentioned so only the essential and exciting weather works were ever included. I sometimes described this meteorology to my coworkers in the weather centre. Often though, the workload and deadlines would come rushing at us and the subtleties of the patterns in the sky and in the satellite imagery would have to be brushed aside. But not today... in addition, this research allows us to estimate when this painting was completed and it was not summer as suggested. 

Sunset Sky Summer 1915
Oil on composite wood-pulp board 8 1/2 x 10 7/16 in.
(21.6 x 26.5 cm)
Tom's Paint Box Size

Tom would have needed a stable platform to paint from in order to capture the details in the cloud structure. The obvious choice would have been his favourite camp on Hayhurst Point looking toward the western shore of Canoe Lake. The lack of distinctive terrain features is in itself an important clue. I have paddled there and was surprised by the simplicity of that western shore. 

 If one looks closely at Tom's painting, a distant forested hill can be seen on the lower right horizon. A back-lit forested ridge also slopes downward to the right. The rocky shoreline of the lake was in the foreground. Of course, there are many such vistas but the shore of Canoe Lake south of Mowat Lodge fits the constraints closely enough as depicted in the following graphic. 

This is certainly a sunset scene looking west because of the weather clues which I will describe. The cloud features establish that the winds were blowing left to right. The overcast clouds on the horizon were characteristic of a mid-latitude weather system and a warm conveyor belt of approaching weather. The source of heat and moisture rising along those isentropic surfaces in the atmospheric ocean was certainly to the south. Tom had to be looking west and the backlit scene required the timing to be a sunset. 

Langmuir Streaks are multiple cloud streets paralleling the wind direction. They occur in a marginally unstable air mass where helical circulations driven by the wind interact to form repetitive, linear cloud patterns. The spacing between Langmuir Streaks is related to the depth and degree of the instability. Langmuir Streaks are described in "Langmuir Streaks – Take the time to Observe and Learn from Nature" and in "Weather Watching Guide for Everyone…" - plus lots of other places in my blogs. 

The rotation evident in the cloud structures is especially interesting and deserves a more thorough explanation. This science is also described in several of my blogs including the following: "A Closer Look at Rotational Clouds", "Cloud Shapes from Rotation" and "The Theory of Unified Swirls".

I never go anywhere without my Coriolis arm and hand. If there is a secret to really understanding cloud shapes, it can be found in using your Coriolis body parts. Remember that the shapes of clouds are sculpted by the relative flows within the atmospheric frame of reference. Your right arm contains all of the tools you will need if you are in the northern hemisphere. Below the equator, your left arm contains the Coriolis insights into the weather. 

Mares tail cirrus (cirrus uncinus) is an excellent example of how to use your Coriolis arm, hand and fingers. Align your Coriolis arm (as in the above graphic) in the direction of the wind at cloud level. The guiding flow can also be determined by watching the cloud drift over the course of a few minutes. Unfortunately, the cloud drift option is not available in a painting or a photograph. Curl your Coriolis fingers in the same direction that the clouds swirl. If your Coriolis thumb points down, you are viewing an anticyclonic rotation. If your thumb points upward, a cyclonic rotation is revealed. The differential advection of these rotations with height results in the airmass either ascending or descending - typically in the direction your Coriolis thumb must point. The amount of cloud should also correlate with whether the air is rising or sinking. The tendency of the surface pressure is also directly correlated with how the air is moving vertically but most people do not carry a pocket barometer. 

The above graphic places Tom within the weather pattern revealed by the cloud. All of the puzzle pieces fit perfectly together. Tom was looking west-southwest in the spring of 1915 before the biting bugs emerged and fishing became his most important interest. The layers of cloud of the warm conveyor belt were rising along their northward journey on the isentropic surfaces. The anticyclonic swirl of the anticyclonic companion of the warm conveyor belt was overhead. The cloud-filled cyclonic companion of the warm conveyor belt occupied the western horizon. 

Combining these facts that Tom recorded in oils almost allows us to be standing with him overlooking his shoulder as he painted. The sunset sky is always beautiful. Notice however that the hues do not even come close to the sunrise colours of the also misnamed "Sunset, Summer, 1915" described previously here. That obvious lack of colour in a sunset sky was the essential clue in revealing this as a spring and not a summer 1915 painting. You might have noticed how I glossed over that statement above!

Lassen Peak erupted in northern California on May 22nd, 1915. Allowing for a couple of days to spread the sulphate aerosols to eastern North America, this subdued sunset painting had to be completed before May 24th, 1915! This sunset sky was observed in the spring of 1915 and not the summer as suggested. Sunsets are typically much more colourful than sunrises after a day of wind stirs dust into the lower levels of the atmosphere. However, this sunset does not hold a candle to the sunrise painted below after the volcanic eruption of Lassen Peak.  

Tom Thomson's Sunset Sky, Summer 1915 as
it would have appeared in his paint box.

Inscription recto: 

• l.r., estate stamp Inscription verso: 
• c., estate stamp; in graphite, 
• u.l., in graphite, 146 (or 47)? Mrs. Harkness; 
• u.l. corner, 15 (circled) Tom Thomson Art Gallery, Owen Sound (967.060) 

Provenance:

• Estate of the artist 
• Louise Thomson (Mrs. J.G.) Henry, Guernsey and Saskatoon, Saskatchewan 
• Tom Thomson Art Gallery, Owen Sound (967.060). 
• Gift of Louise Thomson (Mrs. J.G.) Henry, Saskatoon 1967

This painting bears the "TT-1917" estate stamp so it was among those that J.E.H. MacDonald and Lawren Harris assembled in the Studio Building during the spring of 1918. Tom's father John ensured that each of Tom's siblings received ten works so he probably played a role in getting this particular painting to Tom's older sister Louise (1873-1971) as part of her share. A March 11, 1931 letter from Louise to Blodwen Davies is well worth reading and puts the story of Tom Thomson into the more human and personal perspective that it deserves. 

Louise gave this painting among others to the Tom Thomson Art Gallery, The Tom which in her day was the Art Gallery of Owen Sound. An article in the Owen Sound Sun Times from October 23rd, 1967 tells the story: "Valuable Tom Thomson Works are Presented to Gallery by His Sister." I have presented "Tom Thomson Was A Weatherman" a couple of times at "The Tom" and always stop in to see my friends whenever I happen to be in Owen Sound.  

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: 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!