AVO Level-of-concern Color Code:
In 1989, the Alaska Volcano Observatory (AVO) developed a "color code" to rapidly and clearly communicate the likelihood of an eruption at potentially dangerous volcanoes. This format for summarizing the status of volcano has proven extremely effective in alerting the aviation community to potential ash hazards in the North Pacific region.
- Green:
Volcano is quiet, "dormant" state. No eruption anticipated.
- Yellow:
Small earthquakes detected locally and (or) increased levels of volcanic gas emissions. An eruption is possible in the next few weeks and may occur with little or no additional warning.
- Orange:
Increased numbers of local earthquakes. Extrusion of a lava dome or lava flows (non-explosive eruption) may be occurring. Explosive eruption is possible within a few days and may occur with little or no warning. Ash plume(s) not expected to reach 25,000 feet above sea level.
- Red:
Strong earthquake activity detected even at distant monitoring stations. Explosive eruption may be in progress. Major explosive eruption expected within 24 hours. Large ash plume(s) expected to reach at least 25,000 feet above sea level.
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