This International Standard specifies methods for the determination of snow load on roofs. It will serve as a basis for the development of national codes for the determination of snow load on roofs. National codes should supply statistical data of the ground snow load in the form of zone maps, tables or formulae. The shape coefficients presented in this International Standard are prepared for design application, and may thus be directly adopted for use in national codes, unless justification for other values is available. For examining the effect of the wind on the distribution of snow loads on roofs of unusual shapes or shapes not dealt with in this International Standard or in national standards, suitable models (e.g. tests carried out in a wind tunnel especially equipped for reproducing accumulation phenomena) may give significant results. The annexes describing methods for determining the characteristic snow load on the ground, exposure coefficient, thermal coefficient and loads on snow fences are for information only as a consequence of the limited amount of documentation and available scientific results. In some regions, single winters with unusual weather conditions may cause severe load conditions not taken into account by this International Standard. Specification of standard procedures and instrumentation for measurements is not dealt with in this International Standard.