The Editor,

Journal of Glaciology

Sir,

In the paper by Reference GilbertGilbert and others (1969, p. 58), the passage “The greater snow to the east in the Karakoram mountains produces a lower snow line, e.g. 4 000 m on the Chogo Lungma Glacier (Unter-steiner, 1957)…” is incorrect. In fact, the snow line on the Chogo Lungma Glacier is 700 m higher and therefore hardly lower than on the Afghan glacier discussed in the paper.

The altitude of the snow line was not given in the Untersteiner (1957 [b]) reference quoted in the list at the end of the paper by Gilbert and others, but in an earlier paper by Reference UntersteinerUntersteiner (1957[a], p.5) it was given as 4800 m, according to Wissmann. The snow line of the Chogo Lungma area has been discussed in detail by Reference KickKick (1964), who gave an altitude of 4700 m, but generally in the Karakoram it is 5 000 m and higher.

Gilbert and others have undoubtedly been misled by Reference UntersteinerUntersteiner’s (1957[b]) reference to “firn at an altitude of 4 000 m, but in this case “firn” meant old winter snow that had not melted in June. According to “ Mass-balance terms” (Reference AnonymousAnonymous, 1969, p. 6), “firn” is defined as snow which has passed through one summer. If only Untersteiner had followed this de finition, this misunderstanding would have been avoided; hence such an error may demonstrate the value of clearly defining glaciological terms. But in spite of this, the usage of “firn” for old winter snow in spring time will continue, since this term—even in a definite physical sense—is fixed in common language for all people in Alpine countries and for millions of skiers. This term should not be defined in a totally different manner for its scientific application.

15 March 1969