CSI Algonquin Park II: Tom Thomson’s “Dawn at Round Lake” by Phil Chadwick
Recently a rarely seen painting Dawn on Round Lake (Kawawaymog Lake) by Tom Thomson was sold at auction in Calgary to Albertan Tom Budd for $350,000. Thomson painted the wood panel in 1915 on a small lake near his favorite place, Algonquin Park. Dawn on Round Lake was one of four oil paintings done by Thomson that day while on a hunting trip, and he gave it as a gift to a friend Dr Robert McComb who had accompanied him. The painting has remained in the family for 94 years until one of his heirs decide to put the painting up for sale.
When I used an image of the painting for a brief biography of Thomson in the first installment of "CSI Algonquin Park: Tom Thomson Was A Weatherman and Thunderhead 1913", my friend and fellow meteorologist/painter Phil Chadwick saw it and rapidly did a CSI (creative scene investigation) on it as to the likely weather conditions at the time of the painting and sent it to me. From Phil’s notes, I have, with his permission, turned them into this essay. — Keith C. Heidorn, The Weather Doctor.
CSI Dawn on Round Lake
First, let’s start with what we know about the work. The title gives the first important piece of information, it is dawn. We can deduce from the painting’s yellow tamaracks that it is the fall of the year. Since Thomson shows no sun glint on the water, the sun is at his back so that he is facing westward. (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.)
The painting has large cloud elements, at least in the foreground. Look at how bright white the cloud in the left foreground is – that would also imply lighting from behind Tom. As a general rule of thumb, a backlit cloud is dark in the middle while a frontlit cloud is white in the middle. (The combination of it being dawn and frontlit clouds indicates Tom is looking westerly.) The vertical cloud elements at the top of the panel are most likely altocumulus floccus which indicate an unstable but dry air mass over the region. This would imply warm temperatures are likely this day 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. The layered cloud is probably cirrostratus on the leading edge, lowering to altostratus in the distance. There is no sign of nimbostratus yet so precipitation is sometime off.
The multiple deformation zones/edges 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 the warm front.
Clearly there are two contrasting air masses painted here. Tom is in the dry, unstable air mass with chilly morning temperatures. A cloudier, warmer and possibly precipitating air mass is 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. There is no way that the approaching system can miss Tom.
One solution (probably the best deduction) is that Tom is looking westerly at an approaching low pressure area. The wind, if any is from the east and Tom’s back. This wind, however, has not yet been felt at the surface as the air mass still has a radiation inversion set up after a long autumn night of cooling.