Snow Survey Carried Out In Mount Cook Region

Press, Volume CVI, Issue 31215, 12 November 1966, Page 27

Snow Survey Carried Out In Mount Cook Region

(From Our Own Reporter) TIMARU, Nov. 11.

On the peaks of the Main Divide, and the adjoining high - level snowfields along the north-western boundary of the Mount Cook National Park, precipitation, mostly in the form of snow, is equivalent to about 300 inches of rain a year.

In the Tasman and Godley valleys, rainfall is down to approximately 100 inches yearly, but south of Mount Cook National Park, at the outlet of Lake Pukaki (one of the driest areas in New Zealand), the rainfall averages only about 23 inches a year. The Ministry of Works’ resident engineer for South and Mid-Canterbury (Mr E. R. L. O’Toole) said yesterday that the hydrological team from Timaru, under the assistant engineering scientist (hydrology), Mr T. J. H. Chinn, had been carrying out a snow survey of the Tasman Glacier, covering the winter period, May to November, the chief aim being to determine the snow accumulation for the upper portion of the glacier. Sawdust Used “The method for determining snow falls is by erecting rigid plastic poles each summer, additions to the poles being made on each visit as the depth of snow increases. This gives a continuous length of pole right down to the summer surface of the previous year,” said Mr O’Toole. He added that visits were

made when conditions were suitable, and the remaining height of each pole was measured since the last visit to calculate the accumulation of snow, and a core of the snow was drilled down to the previous snow surface (marked by a layer of sawdust), and the weight of the core was measured to give the water content of the snow. At the completion of each measurement, a new layer of sawdust was spread on the surface, as the new mark for the subsequent measurement, Mr O’Toole continued. A series of seven poles was located along the course of the Tasman Glacier, varying from 3000 feet to more than 7000 feet, said Mr O’Toole. “These measurements will help to determine the snow pattern in the Tasman area, and will no doubt contribute to giving a clearer indication of snow precipitation,” said Mr O’Toole. Similar work

would be carried out in the other sections of the highaltitude regions of the Hermitage area.

The study of the snow precipitation in the area was a long-term one, and the snow survey work was only part of the over-all hydrological programme carried out in the Timaru residency, in which two parties, one at Timaru, and the other at Tekapo, were stationed, said Mr O’Toole. Contractors had started driving piles for the Glencoe bridge, he said. A two-way, reinforced concrete, threespan bridge 105 feet along, it will replace the existing substandard structure, which is a one-way bridge. The bridge is the main link between the Glencoe fan and the Hermitage promontory, and the two pedestrian footways to be incorporated in the new structure are considered necessary because of the traffic between the two areas.