Then began what can only be called the "dressing ritual", the donning of multiple layers of clothing: hats, scarves boots, gloves, over-gloves and over-mittens. (At -35 C., you need to be pretty well-padded to spend the evening standing around outside.)
For an hour or so, there was a lot of activity, with waving bands of green filling the sky. Loops formed and then untied themselves, and fleeting curtains of dancing light appeared and then, just as abruptly, vanished.
Green is the most common color in the aurora, the result of the excitation of oxygen molecules high in the atmosphere caused by incoming charged solar particles. Other colors - red, purple, violet - are possible, but are more commonly associated with stronger solar events. Some of these are not visible to the human eye, but are recorded by film and sensors. So it was not until I had a chance to open images on the laptop that it became clear that tonight's lights did not have some of the red tinges of previous nights.
Whether or not that itself was a kind of indicator of diminishing activity, the lights faded quickly before midnight, and never really re-formed for the rest of the night. What was supposed to be a Big Night, became a quiet evening, and a chance to catch up on some much-needed sleep.