The Volcanic Explosivity Index (VEI) Alert Level was raised to 2 (on a scale of 1-4) on 2 May 2010. Level 1 is Normal and Level 2 is Advisory with an Aviation Alert color of Yellow-Advisory. Based on analysis of satellite imagery, the Darwin VAAC (Volcanic Ash Advisory Center) reported that on 5 May a possible ash plume from Rinjani rose to an altitude of a.s.l. and drifted NW. The plume was not seen in imagery about six hours later. CVGHM (Center of Volcanology and Geological Hazard Mitigation) advised the VAAC that intermittent activity could produce ash plumes to above the caldera.