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March 1, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts from show that any ash clouds that rise above the crater rim today would drift northeastward early in the day and northward 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: Seismic data indicate that parts of the growing lava dome continue to crumble, forming rockfalls and generating small ash clouds that drift out of the crater. Field plans for this week are limited to thermal and visual observations if the weather clears.
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March 2, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift northeastward early in the day and eastward to east-southeastward later.
- Recent observations: Seismic data indicate that parts of the growing lava dome continue to crumble, forming rockfalls and generating small ash clouds that drift out of the crater. The largest earthquake in weeks (about M3) occurred about 11am yesterday. Field plans for this week will be limited to visual observations if the weather clears sufficiently. Thermal imaging will be delayed until next week owing to equipment repair.
March 3, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift north-northeastward early in the day and northward later.
- Recent observations: The crater is mostly clear today and the volcano is emitting a moderate amount of steam. Seismic data indicate that parts of the growing lava dome continue to crumble, forming rockfalls and generating small ash clouds that can drift out of the crater. The bulging ice on the deformed east arm of the glacier continues its rapid trek northward at a remarkably linear rate (about 4 feet per day). Field crews may try for visual observations tomorrow. Next week crews will try to conduct a thermal-imaging flight.
March 4, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift north-northeastward early in the day and northeastward to southeastward later, depending on altitude.
- Recent observations: A moderate steam plume is rising from the around the growing lava dome and at times will be visible above the crater rim. Observations from Johnston Ridge yesterday confirmed continuing crumbling of the margins of the dome accompanied by minor ash production.
March 5, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift northward to southeastward early in the day, depending on altitude, and eastward later.
- Recent observations: The crater is clear this morning with only minor steam rising from the growing lava dome. Recent snow is dusted with ash generated by rockfalls from crumbling of the margins of the dome. Since 5 p.m. last evening, several earthquakes between magnitude 2.5 and 3.0 were recorded. In contrast, the typical rate of occurrence of earthquakes of this size is about one to two per day. A similar pattern was last seen in December 2004 when the lava dome was also going through a period of crumbling.
March 6, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift east-southeastward.
- Recent observations: The crater is in and out of clouds this morning with little steam rising from the growing lava dome. The mini-burst of larger earthquakes that occurred Friday night and Saturday morning has abated and seismicity has returned to its pre-burst level. Rockfall continues from the dome and small ash plumes may rise above the crater rim. This week, field crews will make visual observations and a conduct a thermal-imaging flight.
March 7, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift eastward to east-northeastward early, and shift to a more east-southeastward drift later.
- Recent observations: The crater is again in and out of clouds this morning. Atmospheric conditions yesterday helped produce an impressive steam plume that rose above the rim. If clouds clear today, we may see another steam plume. Photos from a flight over the weekend showed that small rockfalls have continued from the lava dome. However, no new large failures have occurred, nor are new large cracks on the dome obvious. Thus, the recent spate of large quakes is unrelated to obvious decomposition of the dome. Tomorrow, field crews will make visual observations and perhaps retrieve a GPS unit from the crater.
March 8, 2005:
- 8:45 a.m. PST (1645 UTC)
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift eastward early in the day and northeastward 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 volcano is clear this morning and absent a steam plume. However, crews will not be going to the field until later in the week, weather permitting. When they do go out, they plan to conduct visual observations, thermal imaging, equipment maintenance, and retrieve a GPS package. Small earthquakes continue to occur at a pace similar to that of the past several weeks. No large quakes have been recorded since Saturday.
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Mount St. Helens Information Statement,
Tuesday, March 8, 2005, 6:00 P.M. PST
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A small explosive event at Mount St. Helens volcano began at approximately 5:25 p.m. PST. Pilot reports indicate that the resulting steam-and-ash plume reached an altitude of about 36,000 feet above sea level within a few minutes and drifted downwind to the east-northeast. The principal event lasted about 30 minutes with intensity gradually declining throughout. The USGS Cascades Volcano Observatory lost radio signals from three monitoring stations in the crater soon after the event started. The cause of the outage won’t be known until scientists can visit the crater tomorrow to assess the situation, weather permitting. The event followed a few hours of slightly increased earthquake activity that was noted but not interpreted as precursory activity. There were no other indications of an imminent change in activity.
The current hazard assessment for the ongoing eruption mentions the possibility of such events occurring without warning, and the assessment remains unchanged. The eruption could intensify suddenly or with little warning and produce explosions that cause hazardous conditions within several miles of the crater and farther downwind. Small lahars could suddenly descend the Toutle River if triggered by heavy rain or by interaction of hot rocks with snow and ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS) but could pose a hazard along the river channel upstream.
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March 9, 2005:
- 9:45 a.m. PST (1745 UTC)
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift east-northeastward early in the day and shift to an east-southeastward drift later in the afternoon.
- Potential ash hazards to aviation: Under current eruptive conditions, small, short-lived explosions may produce ash clouds that exceed 30,000 feet in altitude. Ash from such events can fall in trace amounts 100 miles or more downwind.
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- Recent observations: A small but significant explosive event occurred yesterday at 5:25 p.m. PST. Pilot reports indicated that the resulting steam-and-ash plume reached an altitude of 36,000 feet above sea level within minutes. The main eruption pulse lasted about 10 minutes, but lower levels of activity persisted for at least another 15 to 45 minutes. Within minutes of the onset of this event, we lost communication with 7 monitoring stations in the crater, but not with any stations outside the crater. The event followed a few hours of slightly increased seismicity that was noted but not interpreted as precursory activity. There were no other indications of an imminent change in activity. Still images from a camera at the northeast end of the crater mouth show a clear component of explosive vertical jetting associated with the event and evidence of ballistics extending at least as far as the north side of the old dome. Aerial photos in of the waning phases of the activity in conjunction with these still images show evidence of small ash flows having moved north and onto to old lava dome. There were reports of fine dustings of ash falling in Ellensberg, Yakima, and Toppenish, Washington between 7pm and 9pm yesterday. As of 2am today, the leading edge of the plume had been tracked to western Montana as a faint and diffuse cloud. Today, field crews will make visual observations and attempt to retrieve and possibly redeploy some of the crater instrumentation stations.
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- 8:00 p.m. PST (03/10, 0200 UTC)
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift east-northeastward early in the day and shift to an east-southeastward drift later in the afternoon.
- Recent observations: A small but significant explosive event occurred at 5:25 pm PST on 03/08, creating a steam-and-ash plume that reached an altitude of 36,000 feet above sea level within minutes. Within minutes of the onset of this event, we lost communication with 7 monitoring stations in the crater, but not with any stations outside the crater. The event followed a few hours of slightly increased seismicity that was noted but not interpreted as precursory activity. There were no other indications of an imminent change in activity. There were reports of fine dustings of ash falling in Ellensberg, Yakima, and Toppenish, Washington between 7pm and 9pm yesterday. According to the Washington Volcano Ash Advisory Center, a faint and diffuse ash cloud was last detected in satellite imagery at 3:30 am PST on 03/09 over western Montana.
- Today, field crews made observations in the crater, sampled ash along the flanks, recovered two damaged monitoring stations, and installed a new seismometer. Observations in the crater found no obvious vent source for the 5:25 pm explosion, and the new dome was found to be remarkably intact. Ballistics up to ~1 m in diameter were seen at distances as far as the northern flank of the old dome, including at all locations where monitoring stations were lost. No ballistics were found along or beyond the rim. Ash deposits in the crater indicate that the plume was very narrow and directed primarily eastwards. Ash up to ~1 inch thick was deposited along the Plains of Abraham east of the volcano.
March 10, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift southeastward at higher altitudes, but remain very near the volcano at lower altitudes.
- Recent observations: The volcano is clear this morning and sporting an intermittent steam plume. There have been no explosive events since 5:25 p.m. local time on Tuesday. After the event Tuesday, seismicity returned to a level similar to that in the several hours prior to the explosion, and it remains at about that level at this time. Yesterday, the new dome was found to be remarkably intact. Ballistics up to ~1 m in diameter were hurled as far as the northern flank of the old dome. No ballistics were found along or beyond the crater rim. Ash deposits were found along a narrow eastward swath. Ash up to ~1 inch thick was deposited along the east flank of the volcano. Although no obvious vent was observed, the distribution of ballistics and ash suggest the explosion emanated from a source very near that of the October 1, 2004 and January 16, 2005 explosions. Today, crews will conduct more visual observations, measure gases, do routine maintenance on some far-field instrument stations, and redeploy GPS units.
March 11, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift lazily north-northwestward to north-northeastward early in the day, and switch to a stronger eastward drift later.
- Recent observations: The volcano is clear this morning and sporting a modest steam plume. Yesterday crews made more visual observations, measured gases, retrieved and deployed GPS units, and collected more ash samples. The source of Tuesday’s explosion from the north-northwest side of the new dome was confirmed. Gases were up slightly from the last measurement, but are well within the range of previous measurements. They do not indicate the presence of a new batch of particularly gas-rich magma. A new GPS unit was placed on the old lava dome, and a unit on the glacier was retrieved. Seismicity remains at a level comparable to that of the days before Tuesday’s explosive event. Today, crews are conducting further visual observations and making needed adjustments to our voice communication system.
March 12, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift south-southeastward early in the day. Later in the day, low-level clouds would drift south-southwestward but higher-level clouds would drift south-southeastward.
- Recent observations: The volcano is clear this morning and emitting little steam. Revised analyses of Thursday’s gas measurements indicate that gas emissions are very low and essentially unchanged from those measured in late February. Hence there is no evidence at this time to indicate that a batch of more gas-rich magma has worked its way near the surface. Seismicity remains at a level comparable to that of the days before Tuesday’s explosive event. Next week, crews plan to deploy new seismometers and GPS units to replace those lost to the explosion.
March 13, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift south-southwestward to southward.
- Recent observations: The volcano is clear this morning. Only a minor amount of steam is rising from several spots around the growing lava dome. Seismicity remains unchanged from levels of the past few days. Scientists are working hard to complete construction of new seismometers and GPS units to replace those lost during last week’s explosion.
March 14, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift south-southeastward.
- Recent observations: The volcano is clear this morning and a minor amount of steam is rising from several spots around the growing lava dome. Seismicity remains unchanged from levels of the past few days. Field work this week awaits the completion of new seismometers and GPS units to replace those lost during last week’s explosion.
March 15, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift southeastward early in the day and east-southeastward later.
- Recent observations: Crews are headed to the volcano this morning to make thermal-sensing and visual observations, to sling a new seismic station to the west side of the 1980-1986 lava dome to replace one destroyed by last week’s explosion, and to make adjustments to a GPS instrument and repairs to a radio repeater. As has been common during this dry winter, the volcano is clear.
March 16, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift eastward.
- Recent observations: Yesterday field crews got good views and thermal images of the growing lava dome. They found no major changes, but noted deposits of small warm flows of pulverized rock that sloughed off the east side of the lava dome and onto the east arm of the glacier. A seismometer was slung by helicopter to the old lava dome and placed at the site of station SEP, which was destroyed in last week’s explosion. The new seismometer is a different type than the old one, so signals on SEP Webicorder plots look different. Also, about 1 p.m. (PST) a crew reduced the gain setting on seismic station YEL, which makes the signals look smaller on the YEL Webicorder plot.
March 17, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift southeastward.
- Recent observations: The volcano is shrouded in clouds this morning, and inclement weather is forecast for the next several days. A new seismometer slung by helicopter to the old lava dome Tuesday is functioning well. We have now replaced a few stations within the crater lost in last week’s explosive event. As time and weather allow, we will gradually replace more of the lost equipment.
March 18, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift eastward, although early in the day high altitude plumes would follow a more east-southeastward trajectory.
- Recent observations: The volcano is mostly shrouded in broken clouds this morning and emitting a small plume of steam. Seismicity remains unchanged over the past several days. Next week as time and weather allow, we will conduct observation flights and gradually replace more equipment in the crater.
March 19, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would east-northeastward early in the day and northeastward later.
- Recent observations: The crater is filled with clouds this morning; rain gages measured minor precipitation during the past 24 hr. No changes were detected overnight in the ongoing patterns of earthquakes and ground deformation.
March 20, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift northeastward.
- Recent observations: Stormy weather has obscured the volcano during the past 24 hours. A rain gage near the mouth of the crater measured about 2 inches of rain and acoustic-flow monitors (AFMs) showed increases in stream flow, but no evidence of debris flows. No changes were detected overnight in the ongoing patterns of earthquakes and ground deformation.
March 21, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift east-northeastward.
- Recent observations: New snow covers the crater and Pumice Plain this morning and clouds continue to obscure the growing lava dome and the upper flanks of the volcano. Tomorrow, weather permitting, we will continue to sling new instruments into the crater to replace those destroyed earlier in the month. Results from the digital elevation model produced from imagery of 21 February show that the highest part of the new lava dome was 12 meters (about 40 feet) higher than on 1 February and that the volume of dome and surrounding uplift had increased by 3 million cubic meters (4 million cubic yards) during that three week period. The average rate of growth continues at about 2 cubic meters (2.6 cubic yards) per second.
March 22, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift in greatly different directions depending on altitude and time of day. Ash clouds at low altitudes (below about 15,000 feet) would drift westward early in the day and southwestward to southward later. Those at higher altitudes would drift eastward to southeastward throughout the day.
- Recent observations: Poor visibility, owing to weather clouds and moderate steam clouds rising from the growing lava dome, caused cancellation of today’s field work. When conditions improve, we will sling new instruments into the crater and make observations.
March 23, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift along trajectories that vary with time and altitude. Low-level clouds will drift southwestward early and shift progressively eastward later. At higher altitudes, drift will vary from northeastward to southwestward trajectories early, and to broad northward to eastward trajectories as the day progresses.
- Recent observations: Today marks the 6-month anniversary of the current eruptive activity. To date, the eruption has been characterized by a remarkably sustained phase of nearly steady dome growth, 7 substantial explosions that have lofted ash thousands of feet above the vent, and brief periods of dome collapse. In the short term, we expect the eruption to continue in much the same manner. Results from analysis of imagery of 21 February show that the highest part of the new lava dome stands at an altitude of 7,682 feet, 527 higher than the old lava dome, and 92 feet below the level of Shoestring Notch on the southeast crater rim. This morning, clouds continue to obscure the volcano. When weather permits, we will sling new instruments into the crater to replace those destroyed earlier in the month.
March 24, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift initially along somewhat westward trajectories and shift later in the day to more northwestward to northward trajectories.
- Recent observations: Although clouds partly obscure the volcano this morning, the crater is visible and the volcano is emitting a moderate steam plume. The recent storms have coated the volcano in snow, and we can probably expect continued steaming in the near future. When weather permits, we will sling new instruments into the crater to replace those destroyed earlier in the month.
March 25, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift northward to eastward at low altitudes, but strongly southeastward at higher altitudes.
- Recent observations: Clouds continue to partly obscure the volcano this morning. These clouds may hinder slinging new instruments to the crater today. Forecasts are for heavy rains and high freezing levels this weekend. Hence, rapid melting of recently deposited snow and subsequent erosion of recently deposited ash could generate small mudflows from the crater over the next few days.
March 26, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift northeastward.
- Recent observations: A couple of inches of rain fell in the crater overnight and rainfall continues this morning. Rapid melting of recently deposited snow and subsequent erosion of ash and debris could generate small mudflows from the crater over the next few days. Two recent magnitude 3+ earthquakes (4:20 yesterday afternoon and 6:15 this morning) are the largest detected since December 2004. Such activity is within the normal range of seismicity recorded during this eruption.
March 27, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift northeastward.
- Recent observations: Clouds and rain obscure the volcano this morning. Since midnight Saturday, nearly 8 inches of rain have fallen at the mountain, raising river levels and increasing flow from the crater. In the past few days, 8 “large” earthquakes (M2 to 3) have occurred. Similar “swarms” of large quakes occurred in November and December. Those in December were attributed largely to breaking up of the whaleback. When weather allows, crews will conduct observation flights and deploy more equipment to the crater. On a historical note, today marks the 25th anniversary of the first steam explosion of Mount St. Helens in 1980, an event that unequivocally showed its reawakening from a 123-year slumber.
March 28, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift eastward.
- Recent observations: Storm clouds continue to obscure the volcano. The spate of larger earthquakes in the magnitude 2.5 to 3.2 range during the past few days appears to be waning. Those looking at PNSN webicorders will see an impressive signal beginning just before 8:30 a.m. PST from this morning’s magnitude 8.5 earthquake in Indonesia on most stations in the PNSN region, but not on stations near Mount St. Helens. That is because the sensitivity of seismic instruments near St. Helens has been turned down so that they will stay on scale and record well the entire size range of events that are occurring at the volcano during the ongoing eruption.
March 29, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift east-northeastward early in the day and east-southeastward later.
- Recent observations: Stormy weather continues with snow forecast for today and intermittently throughout the week. Data from seismic and GPS stations show no significant changes in the level of activity over the past day.
March 30, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE:
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift southeastward.
- Recent observations: The past two weeks have given a taste of what a real Cascade winter would have been like, in contrast to the sunny and dry one that has allowed us to work in the field almost at will. The National Weather Service’s forecast doesn’t provide much hope for relief from storms at least through the middle of next week. Data from seismic and GPS stations show no significant changes in the level of activity over the past day.
March 31, 2005:
- Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE
- Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift northeastward.
- Recent observations: Despite cloudy skies, the crater is mostly clear this morning. The mountain is blanketed in new snow, and discoloration of that snow in the rear of the crater suggests minor ash emissions or rockfalls from the dome have occurred recently. Overnight images from the VolcanoCam reveal a diffuse glow from the dome. The National Weather Service’s forecast indicates we can expect little relief from storms at least through the middle of next week. Data from seismic and GPS stations show no significant changes in the level of activity over the past day.
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