Mt. Fitzherbert

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 would drift broadly north to northwest in the morning, changing to north and northeast by afternoon.

Recent observations: Volcano-related risk was low in the past 24 hours. The lava dome extruded quietly in a pattern familiar by now, namely:

• small earthquakes (magnitude 0-1.5) once every 2-3 minutes;
• slow lava advance westward about 0.9 m per day away from the vent;
• and small rockfalls and resultant uprising small ash clouds from the dome’s northwest face, its most precipitous side.

For seismic aficionados who revel in the PNSN webicorder tracings, our crater seismometer, code-named SEP and serviced Feb. 24, best displays the protracted small rumbling that accompanies the larger rockfalls. At night these rockfalls breach the hotter core beneath the lava’s cooled skin and reveal incandescent rock (hotter than about 500 deg C).

Wet snow on powder in the past three weeks has increased the avalanche risk expectedly. But those choosing to snowmobile, ski, or snowshoe in the permitted areas on the volcano’s flanks should remain particularly alert near steeper slopes, where the likelihood of small local snow avalanches may be heightened further by sporadic earthquakes in the magnitude 2-3 range.