WMO Guide to Instruments and Methods of Observations (GIMO)

Volume II “Measurement of Cryospheric Variables” of the Guide on Instruments and Methods of Observation (GIMO) is a contribution of Global Cryosphere Watch (GCW) to ensure high quality and consistent observations and measurements of cryospheric variables made in accordance with accepted standards. Emphasis is put on establishing standards in agreement with the existing ones as well as with guidelines for observations of single cryospheric variables, some of which are routinely used. IACS members contribute substantially to this volume.
Chapter II of Volume II is dedicated to the measurement of snow. The chapter is based on the ICSSG and should be looked at as a regular update to the classification.

The 1954 classification

In 1954, The International Commission on Snow and Ice (ICSI) of the International Association of Scientific Hydrology (IASH) issued this first version of the “The international classification for snow (with special reference to snow on the ground)“. The document was published as “Technical Memorandum No. 31 by the Associate Committee on Soil and Snow Mechanics, National Research Council, Ottawa, Canada.“.
Vincent Schaefer (USA), George Klein (Canada), and Marcel de Quervain (Switzerland) put together three slightly different approaches to one “basic framework which may be expanded or contracted to suit the needs of any particular group ranging from scientists to skiers“.
It is worth to note that this spirit survives through to the most recent guide on measurement of snow (see