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 east-northeast, changing to southeast by afternoon.

Recent observations: Dacitic lava continues to extrude quietly in the crater of Mount St. Helens. In the next day, it is unlikely that explosions or other hazards will change the low-level risk that has characterized the ongoing eruption for the past 10 months. This estimate is based on instrumental evidence and past history, inasmuch as wintry weather precludes viewing the crater and will likely sprinkle another 25-50 cm of snow over the weekend. Seismometers record small earthquakes about once every 2-5 minutes. Called drumbeats or heartbeats because of their regularity, since Christmas they’ve taken on some trifling arrhythmia (if we may push the cardiac analogy). Two GPS receivers on opposite sides of the growing dome are moving apart at about 1 cm per day, as they have been since the year began. Their separation probably results from being shouldered aside by the extrusion. Tiltmeters about 400 m from the vent are inclining at about 1-2 microradians per day.