Volcano Alert Systems
Nearly 45,000 people are being housed in evacuation camps in preparation for an imminent eruption of the Mayon volcano in the Philippines. The status of the volcano is currently at Level 4, which means that eruption is imminent. Level 5, the highest level, means that eruption is taking place.
In the US, the US Geological Survey Volcano Hazards Program uses a four-level alerting sytems, Normal, Advisory, Watch, and Warning. Currently, only two volcanoes in the US are designated above Normal status: Kilauea (Watch) and Mauna Loa (Advisory), both in Hawaii. Mount Redout, the Alaskan volcano that erupted last spring, has returned to Normal status.
Update: Mount Redoubt’s status was changed to ADVISORY on Sunday, December 27, 2009.