Figure 3. The extent of the August 19, 1992 Crater Peak/Spurr volcanic cloud as observed by C-band radar (5 cm), 85 GHz SSM/I (3.5 mm), and Band 4 AVHRR (10.8 um). The outline of the volcanic cloud was subjectively determined by interpolating between volcanic cloud pixels and non-volcanic cloud pixels based on volcanic cloud pixels having lower brightness temperatures than non-volcanic cloud pixels.