Mt. Fitzherbert

Aerial views taken on 2005-Jan-19

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

Recent observations: Yesterday a crew investigated the effects of an event that occurred about 3 a.m. (PST) on 16 January. Pictures are posted on our web site. The 17-minute-long event was an explosive emission of ash and blocks from the vent area at the north end of the growing lava dome. A shower of ballistic fragments pockmarked a snow-covered area up to several hundred meters northeast of dome with craters up to one meter in diameter. New instruments deployed on 14 January were severely damaged, as was an older GPS instrument. Ash fell thickly in east and west parts of the crater and drifted eastward over the rim depositing a thin layer of gray ash on the east flank outward for at least 3 kilometers. The scale and impact of the explosion was similar to that of 1 October 2004, which was witnessed in clear weather. Analysis of a digital-elevation model made from photographs taken on 3 January provides new information about the size of the growing welt and lava dome. Since last measured on 11 December 2004, the lava dome has maintained its 475-meter length, which is constrained by the old lava dome and crater wall, but has widened from 310 m to 410 m. Its highest point is 7 m higher. The entire welt and dome has increased in volume from 30 to 34 million cubic meters, an average rate of about 2 cubic meters per second. These results suggest that the rate of lava extrusion has decreased from autumn 2004 rates.