Sir,
While conducting field research on Kaskawulsh Glacier, Yukon Territory, Canada, an unusual phenomenon was observed which in this instance related to moulin formation. 30 m. from the writers’ position, at about 11.00 hr. on 30 June 1966, a vertical spout of water suddenly rose from the glacier surface. This was in the same area where Reference DewartDewart (1966) observed several moulins.
The spout of water lasted 7–10 sec. and reached a maximum height of 4–5 m. The only sound noted to accompany the phenomenon was the noise of rushing water; there was no sharp sound of fracturing ice. Immediate investigation of the site revealed that the water had issued from a vertical fissure 7–8 cm. wide and orientated perpendicular to glacier flow (Fig. 1).
Fig. 1. Site of the water-spout, central arm of Kaskawulsh Glacier, looking. south; 30 June 1966
The site, which at this time of year was in the vicinity of the snow line, was covered with crusted snow to a depth of 15–20 cm. The glacier ice at the fissure itself, however, was blown and washed bare for a distance of more than 1 m. along the length of the fissure and 25 cm. on either side. This rectangular pattern of snow-free ice, along with the splatter pattern left by the falling water in the snow, suggests that in cross-section the fountain of water was tabular rather than columnar.
Water from surrounding slush areas began to flow into the fissure almost immediately. Within 2 days it was apparent that a distinct circular moulin was developing (Fig. 2). By 9 July the original ice fissure had closed, leaving only a circular hole approximately 0.5 m. in diameter (Fig. 3). This opening was not only being maintained, but enlarged, by two tributary streams diametrically entering it. Final observations on 2 August revealed that the moulin had a diameter of approximately 1.25 m. and the two entering streams had entrenched approximately 1 m. into the lip of the moulin (Fig. 4). Throughout the observation period there was no evidence suggesting recurrence of spouting action.
Fig. 2. Developing moulin at the site of the water-spout, looking south-south-east; 2 July 1966
Fig. 3. Moulin at the site of the water-spout with two tributary melt-water streams, looking west up-glacier (ice-axe at right for scale); 9 July 1966
Fig. 4. The two streams shown in Figure 3 entrenched into the lip of the enlarged moulin, looking west; 2 August 1966
An aspect of this moulin, not observed in others of the immediate area, was an irregular pulsation of air from the mouth carrying aloft a fine spray of water. This discharge of air from the moulin was first observed on 15 July and continued to the end of the observation period.
3 March 1967
