Mudflows and some flooding could be expected in the Cathedral River valley north of the volcano. Airborne ash hazards to aircraft may be considerable if a large explosive event occurs but much less severe during a typical Strombolian phase. AVO has a seismic network of six stations near the volcano and will continue to monitor the volcano's seismic activity. Definitions of the colors reflect AVO's interpretations of the behavior of the volcano. Definitions are listed below followed by general descriptions of typical activity associated with each color.
Volcano is restless.
Explosive eruption may occur with little or no additional warning. Extrusion of lava dome or lava flow may be occurring. Major explosive eruption is in progress or expected within 24 hours. Potentially hazardous ash plume to 25,000 feet ASL or more is expected or has been confirmed. Seismic events indicative of eruption have been sporadic through the afternoon.