Sufficient data of roof snow depths for structural design are not available because there are difficulties in measuring the intensity and distribution of snow depths by climbing onto roofs. Especially, on sloped roofs, snow sliding caused by the measurement technique makes the long-term measurement almost impossible in some cases. In the present paper, the method of aerial photogrammetry is discussed to be applicable in surveying snow depths on roofs over a broad area. First, measurement errors of roof snow depths by aerial photogrammetry are investigated. Then, examples are shown in applying to the measurements of snow depths on various types of roofs.
