Mt. Fitzherbert

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 north-northwestward to northward. Under these conditions, Johnston Ridge and the east end of Highway 504 could receive ash fall.

Recent observations: Additional analysis of data from Wednesday's field work shows an interesting pattern. Thermal-sensing data reveal a hot zone around the perimeter of the western part of the new lava dome, an area about 400 meters long by 50 meters wide. In the past few months, such a hot zone has been restricted to the north end of the dome, where lava was being extruded to form a succession of whaleback-shaped domes, which chiefly moved southward. Coupled with the orientation of grooves that form as the dome extrudes from the vent, these new thermal data suggest that much of the western part of the dome is moving upward, as well as southward. We would like to place a GPS spider on this part of the dome to measure its rate of movement, but stable spots are scarce because this part of the dome is also producing a lot of rockfalls.