Tom Thomson's Black Spruce in Autumn from 1915

 Black Spruce in Autumn, 1915, (cold frontal passage)

Thomson applied two layers of coloured "ground" on the panel before he painted this view on the western shore of Canoe Lake. Tom wanted this record of weather to last. That portion of the lake is relatively shallow with numerous stumps and rocks. I suspect that Tom simply beached his canoe on some obstacle and painted from a very low vantage point looking upward into the sky.  A cold front with showers had just passed through Tom’s location and he probably felt compelled to paint since the rain would have prevented him from doing so. How do we know all of this? 

Black Spruce in Autumn, Fall 1915
Oil on composite wood-pulp board
8 9/16 x 10 9/16 in. (21.7 x 26.8 cm) (Tom's Paintbox size)
McMichael Canadian Art Collection, Kleinburg (1966.14) 

I first studied this painting in the mid-1990s and was told that considerable funds were required to include any of Thomson's art in my book "Tom Thomson Was A Weatherman". The sums certainly added up and were well beyond my means. As a result, I constructed a blurred image on which I could label what Tom saw and painted.  Apparently, Tom's art is now in the public domain, a hundred years after his passing in 1917. Being a meteorologist and not a lawyer, I am not certain what "being in the public domain" really means. I simply wish to share Tom's passion and reveal why he painted what he did while respecting the laws of the land. 

Tom painted all of the weather clues very clearly and 
in plein (plain) sight. Being a meteorologist certainly helps. 

What we know. The point form layout of these facts reveals the analysis and diagnosis process applied during CSI - Creative Scene Investigation. 

• The low horizon at the lowest third of the panel, identifies this painting as another skyscape.
• The deciduous trees were full of autumn colour, so this sketch's timing must be in later September or October. The colours in Algonquin tend to reach a peak in late September. 
• The clouds were towering cumuli that were very vertically developed and more than tall enough to produce locally heavy rain showers. 
• The tops of the towering cumulus clouds were tilted from right to left consistent with westerly or northwesterly wind shear. 
• Daytime heating in an unstable air mass is the most likely cause of these towering cumuli which are also referred to as cumulus congestus. As a result, we can rule out a warm frontal system which would have been accompanied by cirrus and other warm frontal layered cloud associated with a warm conveyor belt. 
• Otherwise there was only patchy altocumulus in the sky.
• It would take most of the day to develop this scale of instability from daytime heating in the autumn so the daily timing of this sketch was mid to late afternoon.
• The towering cumulus appeared to be organized along a line which could be a simple surface trough or a cold front. Given the time of year, I would expect that a cold front would be required to produce a cloud line like this that was so fully developed.
• There was no sun glint on the lake so Tom is definitely not looking toward the sun as typically anticipated for plein air painters. 
• The trees in the foreground are dark and in shadow, so Tom’s view must have a southerly component.

Another view of Tom's Black Spruce in Autumn so you can 
relate the points to his brush strokes part way through the CSI.

• The clouds are well-illuminated and not backlit so Tom must be looking a bit more to the southeast. For the clouds and distant deciduous tree line to be so well illuminated, both the distant shore and cloud line must have an orientation toward the west and the late afternoon sun. 
• The distant shoreline tends to get smaller and more distant from left to right.
• The tallest clouds along the convergence line tend to be to the right. This is typical for convection along a cold frontal line where the largest and most intense convective cloud tends to be the last one in the line – tail end “Charlies”. These taller towering cumuli are most likely to produce a “passing shower” as they have access to higher values of heat and humidity - fuel for the stronger towers of convective cloud.  
• Note that some of the clouds are darker indicating that they are composed of larger cloud droplets. These larger cloud droplets grow at the expense of smaller cloud droplets. This process takes time and thus these clouds are probably older. These older clouds have probably already precipitated. 
• The wave action was significant even with the limited fetch from the west. The northwesterly surface winds must have been significant.
• The surface winds would be veered slightly  (turned clockwise from a satellite vantage) due to friction compared to the direction of the upper winds revealed by the clouds. 

A map is required to show how this geometry works out. Tom's sketch reveals interesting variations in the orientation of the main elements.

Tom's southerly view with the dark trees,
the shoreline with deciduous trees,
towering cumuli with rain showers, the yellow sun and 
the associated surface wind directions.

An example of similar towering cumuli that Tom would 
have viewed on that 1915 autumn afternoon in Algonquin.

The Most probable CSI Solution

An active (anabatic) cold front had just passed Tom’s painting location. Possible brief but heavy showers and a wind shift to the west would have marked the cold frontal passage. Ahead of the cold front, it would have been warmer and more humid for a fall day. Behind the front, it was going to become cooler, drier, and windier. Simply, Tom painted the back flank of a cold front that had just crossed Canoe Lake.

Black Spruce in Autumn by Thomson from 1915 and on
another October day in 2016 when I paddled Canoe Lake

On a magical day in October 2016,  I was all alone on Canoe Lake. The weather forecast of torrential rain kept the people away. I quietly paddled every nook and cranny looking for Tom and I saw his plein air sketches at every turn. The deformation zone held the rain at bay until 3 pm by which time I was putting my canoe on the car. Sometimes it pays to be a weatherman. 

It was a very special day gently stroking my canoe with the memory of a friend I had never met although knew very well. I saw 49 paintings that day and they can be found in my "Canoe Lake Collection" on Fine Art America.  I may have followed in the footsteps and the paddle strokes of Tom Thomson but I have to paint my own way.

The science clearly hidden in the oils and brush strokes of Tom Thomson is sound. But no one can be absolutely certain. I was not there painting with Tom as much as I would have loved to be. It is important to keep an open mind and that is how we learn - even from our mistakes. 

Warmest regards and keep your paddle in the water,

Phil the Forecaster Chadwick 

PS: For the Blog Version of my Tom Thomson catalogue raisonné, Google Search Naturally Curious "Tom Thomson Was A Weatherman - Summary As of Now" or follow this link “http://philtheforecaster.blogspot.com/2022/10/tom-thomson-was-weatherman-summary-as.html”

Tom Thomson's “Dawn on Round Lake" tells a story...

Creative Scene Investigation "Dawn on Round Lake"

Thomson painted the wood panel in November 1915 on a small lake just west of his favourite place, Algonquin Park. "Dawn on Round Lake" was one of four oil paintings completed that day while on a hunting trip. Tom was staying at Island Camp with park ranger and friend Tom Wattie (from South River) and Dr. Robert  McComb. Apparently, "Dawn on Round Lake" was painted at Mud Bay on what is now called Kawawaymog Lake.

Tom gifted this particular painting to Dr. McComb. The painting remained in that family for 94 years and then was sold at auction in Calgary to Albertan Tom Budd for $350,000 on April 19, 2009. The painting was expected to fetch $600K but only Tom Budd raised his hand. Mr. Budd expects to donate the painting someday.

Kawawaymog Lake. Some islands in the middle were probably
the location of the "Island Camp"

Dawn on Round Lake [Kawawaymog Lake]
November 1915 Oil on wood 8 1/4 x 10 1/2 in
Tom Thomson's Sketch Box size

First, let’s start with what we know about the work. The title gives the first important piece of information: it was dawn. We can deduce from the painting’s yellow tamaracks that it was also the fall of the year – actually November because the deer rut and hunting season were on. Rifle season for deer typically starts on the first Monday in November. 

Since Thomson shows no sun glint on the water, the sun was at his back. As a plein air painter, Tom would normally paint with the sun to his back anyway. Painting while staring into the sun is difficult at best and at worst, dangerous for your eyes. This typical situation is confirmed by the bright fall colours of the subject matter. The shadowed side of a backlit subject would be in shade and not nerarly so colourful.  So we know through indirect logic that Tom was facing westward. 

The painting has large cloud elements, at least in the foreground. Look at how bright and white the cloud in the left foreground is – that front-lit cloud also confirms the lighting from behind Tom. As a general rule of thumb, a backlit cloud is dark in the middle while a front-lit cloud is white in the middle. 

The vertical cloud elements at the top of the panel are altocumulus floccus which indicates an unstable but dry air mass over the region. The surface temperatures were sure to climb with continued daytime heating. Such an air mass is typically unstable on the outer edge of an approaching low pressure area.

The layered clouds in the distance coming up from the horizon imply a completely different type of air mass — stable with layered moisture — consistent with a low pressure area and gentle lift in the atmosphere. This is the warm conveyor belt of the approaching weather system. The layered cloud is the cirrostratus on the leading edge, lowering to altostratus in the distance. There was no sign of nimbostratus yet so the precipitation was still several hours away. The linear nature of each layer of cloud is the result of the deformation zone. 

The multiple deformation zones that encircle the cloud are characteristic of the leading edge of the warm conveyor belt in the conveyor belt conceptual model of mid-latitude dynamic systems. The deformation zones occur at ever lower levels in the atmosphere until the warm air reaches the surface — the lowest deformation zone is actually the warm front. 

The deformation zone process is very three-dimensional and occurs throughout the atmosphere but is only made visible by the quasi-horizontal layers of the cloud where those layers of moisture intersect with the flow. Perhaps the accompanying graphic might assist with these concepts.

The anticyclonic companion (see The Relativity of the Companion Flows in the Warm Conveyor Belt for more explanation) of the warm conveyor belt was directed toward Round Lake. This is supported by the more stratiform nature of the cloud with the approaching storm. The overhead floccus that certainly attracted Tom's attention would have also been lifted by the "cyclonic swirl" that is an essential part of the deformation zone conceptual model. 

Clearly, there were two contrasting air masses painted here. Tom was in the dry, unstable air mass with chilly morning temperatures. A cloudier, warmer, and probably precipitating air mass was on the way. Note how the deformation zones show no sign of curling/curving so that the warm air mass that they encircle extends far to the right and to the left. This was a large storm. There is no way that the approaching system was going to miss Tom.

The CSI solution is that Tom was looking westerly at a very large approaching low pressure area. The wind, if any was from the east and Tom’s back. This easterly cold conveyor belt wind, however, had not yet been felt at the surface as the air mass still had a radiation inversion set up after a long autumn night of cooling. All of these weather clues were clearly hidden in the bold brushwork of Tom Thomson just waiting to be discovered.

Warmest regards and keep your paddle in the water,

Phil the Forecaster Chadwick

PS: For the Blog Version of my Tom Thomson catalogue raisonné, Google Search Naturally Curious "Tom Thomson Was A Weatherman - Summary As of Now" or follow this link “http://philtheforecaster.blogspot.com/2022/10/tom-thomson-was-weatherman-summary-as.html”

Tom Thomson's “A Northern Lake" Was the Belt of Venus Sunrise

There are many entries in the Tom Thomson catalogue with the word “lake” employed. “Northern” is often used in conjunction as well. A classic example is “A Northern Lake” in the Art Gallery of Ontario collection. The painting was apparently created in 1911, 1915, or maybe 1916 depending on who you listen to. The  "TT Estate Stamp" appears prominently in the lower left corner so Tom didn't bother to sign this work either. I will leave the actual creation date for this observation to the experts. I wish to focus on “what” and “why” because I feel that the name totally misses the point of Tom's sketch. 

"A Northern Lake" circa 1916; W26.7 x H21.6 cm (overall)
10.5 x 8.5 inches - sketch box size
oil on composite wood-pulp board
 Gift from the Reuben and Kate Leonard Canadian Fund, 1927

This is a skyscape with the horizon at the lower third of the sketch box panel. There is indeed a lake in the foreground and what appears to be some ice along the shoreline. There was no foliage on the trees. Tom certainly painted this to record the rose and pink colours in the sky but what was he looking at?

There are just two viable options. 

• One is the rose colour resulting from front-lit cloud with the sun on his back. The soft and diffuse edges of the altostratus or cirrostratus cloud could explain what Tom was trying to capture with his oils. 
• The other is that Tom was looking at the eclipse of the atmosphere by the shadow of the earth - the Belt of Venus (associated with the Greek goddess Aphrodite and Roman goddess Venus - not the second planet in the Solar System). 

A backlit cloud is not an option given the strong colours of the lake and marsh and even the distant hills. Tom’s subjects were clearly not in strong shadow. (See graphic explanation below)

Everyone sees this phenomenon twice a day but rarely ever takes any notice. Perhaps the best way to decipher Tom’s motivation is with some actual images. 

Singleton October Sunrise with Arctic Sea Smoke rising from 
the lake. The skies were clear overnight and the temperatures
plummeted. No more swimming for me... The dark grey
on the horizon looks like altostratus coming at us...
but it was the shadow of the earth on the lower atmosphere -
the Belt of Venus was the pink above that. 

The same scene twenty minutes later with only fog in the sky.
The grey horizon disappeared as the sun continued to rise.
The grey was not clouds at all. .

The earth casts a shadow on the lower atmosphere twice a day at your location: the first at sunrise if you gaze toward the west and the other at sunset looking toward the east. The shadow in the sky lasts only about 15 minutes - just long enough to boldly observe and lay the oils on a sketch. This phenomenon is referred to as the “Belt Of Venus” and that is the what and why of Tom's sketch. 

The Belt of Venus, also called Venus's Girdle or the anti-twilight arch is an atmospheric phenomenon visible shortly before the sun rises or after sunset, during civil twilight (the geometric center of the sun is within 6 degrees below the horizon). The pinkish glow surrounds the observer and extends 10 to 20 degrees above the horizon.

Any graphic to adequately explain this phenomenon must be greatly distorted.  

• Remember that the atmosphere is actually quite thin similar to the skin of an apple. The troposphere where almost all weather occurs extends only 8 to 14.5 kilometers high (5 to 9 miles). This part of the atmosphere is dense and thus the most likely to scatter light creating the visual effects that we enjoy. 

• Also, recall that the sun is far from the earth at about 8.3 light-minutes away. On average, the earth is 150 million kilometers away from the sun.

• The earth is only 12,742 km in diameter. The dimensions of the earth are dwarfed by the distances involved. 

As a result, the following graphics are extremely distorted.

The following graphic explains the optics of the Belt of Venus. 

1. Observer's line of sight away from the sun.
2. The sun is within 6 degrees below the observer's line of sight toward the sun.
3. Light from the sun passes through a very long atmospheric path. Short wavelengths are scattered out of the sun's beam leaving only longer red waves of light.
4. The observer sees reddish light backscattered from the illuminated atmosphere.
5. This is the shadow of the earth and this portion of the atmosphere is not illuminated by the direct beam (refraction and diffraction can get light into this region but let's keep this simple)

“A Northern Lake” Diagnosed

Perhaps an image that was taken by my friend George Kourounis, RCGS Explorer In Residence, Nat Geo explorer, & TEDx speaker will help. George was on a sunrise balloon ride in Türkiye facing west just before the sun rose up from behind him. The Earth itself gets in the way of the sunlight and casts a shadow on the lower atmosphere. The pinkish shade above the shadow is the Belt of Venus. 

Image looking west at sunrise by George Kourounis,
RCGS Explorer In Residence, with permission

Tom painted the Belt of Venus most likely at sunrise on a chilly morning. He was a morning person much like me. His subject was the sky. 

I must confess that a very similar and equally convincing argument can be made that the pinkish area in Tom's sketch is actually sunrise, front-lit cirrostratus, or altostratus associated with a warm conveyor belt approaching from the west. 

The sharp and dark horizontal line on the lower horizon would be the nimbostratus deformation zone that I have mentioned so many times. Rain could be on the way. 

I cannot be absolutely certain. I was not there painting with Tom as much as I would have loved to be. It is important to keep an open mind and that is how we learn - even from our mistakes. 

Warmest regards and keep your paddle in the water,

Phil the Forecaster Chadwick

PS: I wish to also explain why a backlit scene is not an option due to the strong colours that Tom included in his foreground. Here is the explained sunset from the October day when this Blog was posted. The skies were clear and this image was taken minutes after the sun set below the western horizon of Singleton Lake. 

Backlit Scene Looking West toward the Sunset Sky

PSS: Here is an image from October 2022 showing sunrise altostratus on the western horizon. The cloud was front-lit but if I had taken the picture earlier than 7:30 am, it might have been confused with the Belt of Venus. I missed that opportunity but I was close...  

7:30 am Saturday, October 15th, 2022

PS: For the Blog Version of my Tom Thomson catalogue raisonné, Google Search Naturally Curious "Tom Thomson Was A Weatherman - Summary As of Now" or follow this link “http://philtheforecaster.blogspot.com/2022/10/tom-thomson-was-weatherman-summary-as.html”