Mt. Fitzherbert

Aerial views taken on 2005-Feb-16

Potential ash hazards: Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that any ash clouds that rise above the crater rim today would drift westward early in the day and northwestward later.

Potential ash hazards to aviation: Under current eruptive conditions, any ash clouds produced are unlikely to exceed 15,000 feet in altitude. Ashfall from such events rarely reaches more than 20 miles downwind. If the lava dome continues to grow over the next several months, it will become able to produce larger ash clouds that reach higher altitudes and extend farther downwind.

Recent observations: The GPS unit deployed on the east arm of the crater glacier on Wednesday is moving northward at about 4 feet per day. This rapid rate of flow is consistent with the thickening of the glacier that has resulted from its compression between the growing lava dome and east crater wall. Results of Wednesday's thermal-imaging flight suggest that a longitudinal crack is developing along the top of the new lava dome. Similar to what happened in mid-December, the long smooth whaleback-shaped dome may be starting to crack apart. During such a process, the probability of rock avalanches increases and with that an increased chance of more ash clouds rising above the crater rim than we've witnessed in recent weeks.