Avalanche Precautions

Press, Volume CIV, Issue 30762, 28 May 1965, Page 12

Avalanche Precautions

Avalanche types, precautions and rescue were the subject of an address by Mr L. Eisielstein, a Fulbright lecturer at Lincoln College, to about 60 skiers at a meeting og the Canterbury Ski Patrol last evening. Mr Eisielstein is a fully qualified member of the 10,000-strong American Ski Patrol. “There are two main types of avalanche, the loose snow and slab avalanches,” he said. “Victims caught in the loose snow type have about two hours to live but those trapped in a slab avalanche, the more common type in New Zealand, have 15 minutes. “However, the loose snow type moves at speeds in excess of 100 miles an hour while slabs are much slower.”

He said the slope of the mountain was one of the surest ways to predict avalanche conditions. It was rare for avalanches to form on slopes greater than 60 degrees or less than 30 degrees as snow did not lie on the former and could not gather momentum on the latter. “Most skiers are inclined to over-estimate slope, few can ski on more than 50 degrees, so the naked eye is not always enough for a skier to judge," said Mr Eisielstein. Rougher slopes required a greater angle and mass for an avalanche and vegetation often helped. “But Canterbury’s tussock growth aids avalanches and it gives them a smooth run. In Europe the ski-fields are grazed to shorten the grass before the first snow fall.

“Temperature change is the greatest aid to avalanches,” he said. “The recent German avalanche was started by a

temperature change of one degree.

“The surface of a snow pack has a higher temperature than the base, often a difference of 15 degrees, and the base often forms ball-bearing shaped pellets. These are very unstable and are why avalanches always go right to the ground.” Wind action generally lowered the snow level and provided stability, lie said. However, when the drift snow was not bonded to the base, an unstable slab was formed. Mr Eisielstein said there were many way? of judging the existence of avalanche conditions.

These included the depth of the snow, its roughness, depth of new snow, crystal structure of the snow, its moisture content, temperature changes, higher snow levels around protruding obstacles indicate settlement, and wind speeds of more than 25 miles an hour are dangerous. Mr Eisielstein gave a detailed account on how to conduct a search and rescue operation. He gave a 15-point schedule for teams to follow, emphasising that only expert skiers should be considered for rescue work. Mr P. Baudinet, an instructor at Craigieburn, gave a short address on evasive methods.

'“Buddy Werner, the American Olympic skier, was killed in an avalanche because he tried to outrun it,” said Mr Baudinet. “The terrific windpressure started another avalanche to his right and that one got him, not the one following him. “Ski to the side and lie flat or you will be blown back into it and, if you find you cannot escape, free yourielf of anything cumbersome like skis or packs.”