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May 1, 2006:
- 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. During such eruptions, changes in the level of activity can occur over days to months. 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.
- Wind forecasts show that any ash clouds that rise above the crater rim today would drift principally to the east and southeast.
- 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 travel 100 miles or more downwind.
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- Recent observations: Views of the volcano from Johnston Ridge have been mostly obscured by low clouds this morning, although skies are forecast to clear as the day proceeds. The volcano’s eruptive behavior remains quiescent and unchanged. The extruding new dome continues to advance westward at a rate of about one meter per day, and very small earthquakes continue to occur roughly once each several minutes.
- *** This line included in daily update but excluded for rest of month on this page.
May 2, 2006:
- 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 principally to the south and southeast.
- Recent observations: Seismicity and other eruption indicators remain at low background levels, and dome growth continues at roughly the same pace as in recent weeks. Analysis of time-lapse photographs taken by a field crew on Friday, April 28, indicate that lava is emerging from the vent at a rate of 1-2 meters per day, consistent with earlier estimates. A GPS instrument on the new dome west of the vent continues to advance westward at a rate of about 1 meter per day. Clear weather is providing good views of the volcano from Johnston Ridge today, and it is forecast to continue through Friday. Additional field work is planned later this week.
May 3, 2006:
- 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 principally to the west and south.
- Recent observations : The volcano?s eruptive behavior remains quiescent and unchanged. Seismicity and other eruption indicators remain at low background levels, and dome growth continues at roughly the same pace as in recent weeks. Lava continues to emerge from the vent at a rate of 1-2 meters per day. A GPS instrument on the new dome west of the vent continues to advance westward. Clear weather is providing good views of the volcano from Johnston Ridge today, and it is forecast to continue through Friday. Additional field work is planned later this week.
May 4, 2006:
- 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 principally to the southwest.
- Recent observations : The volcano?s eruptive behavior remains quiescent and unchanged. Seismicity and other eruption indicators remain at low background levels, and dome growth continues at roughly the same pace as in recent weeks. Lava continues to emerge from the vent at a rate of 1-2 meters per day. A GPS instrument on the new dome west of the vent continues to advance westward. Clear weather is providing good views of the volcano from Johnston Ridge today, and it is forecast to continue through Friday. Field work consisting of site maintenance and observations and routine measurements is planned for today.
May 5, 2006:
- 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 principally to the northwest early in the day, shifting to northeast later in the day.
- Recent observations: The dome-building eruption that began in October 2004 continues at the same pace as in recent days, accompanied by low background levels of seismicity and other eruption indicators. A GPS instrument on the new dome west of the vent continues to move westward nearly 1 meter (3 feet) per day. Field crews had a successful day at the volcano yesterday. Three of four time-lapse cameras on the crater rim or floor are again operational, returning images that show continued growth of the active part of the new lava dome. A fourth camera remains buried in a snow cornice on the south crater rim. Scientists collected another rock sample from the vent area and measured emission rates of volcanic gases. Preliminary analyses indicate no significant changes from past trends.
May 6, 2006:
- 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 principally to the east or southeast.
- Recent observations: The eruption continues. Seismicity and motion of the west part of the new dome remain at levels typical of the past few days. Views of the crater from the U.S. Forest Service’s Johnston Ridge Observatory and from cameras on the crater rim and floor are obscured by clouds this morning. Forecasts call for cloudy weather again tomorrow, with clearing starting on Monday. Next week should provide some excellent views of the eruption site from Johnston Ridge Observatory.
May 7, 2006:
- 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 principally to the east.
- Recent observations : The eruption continues. Seismicity and motion of the west part of the new dome remain at levels typical of the past several days. Views of the crater from the U.S. Forest Service's Johnston Ridge Observatory and from cameras on the crater rim and floor are obscured by clouds this morning. Forecasts call for cloudy weather today and though bothersome when trying to see Mount St. Helens, it should start clearing Monday. Next week should provide some excellent views of the eruption site from Johnston Ridge Observatory.
May 8, 2006:
- 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 principally to the southeast.
- Recent observations: Seismicity and motion of the west part of the new dome remain at levels typical of the past few days. Low clouds are obscuring views of the crater from Johnston Ridge Observatory this morning, but forecasts call for clearing this afternoon and mostly sunny skies for the next few days.
May 9, 2006:
- 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 principally to the southeast.
- Recent observations: Seismicity and motion of the west part of the new dome remain at levels typical of the past few days. Weather forecast calls for mostly sunny skies for the next few days, so the crater is likely to be visible from Johnston Ridge Observatory.
May 10, 2006:
- 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 broadly northward at low altitudes and east-southeastward at higher altitudes early in the day. Later in the day any ash clouds would drift east-northeastward.
- Recent observations: Analysis of recent photographs from remote cameras shows that a slab of rock about 70 meters (230 feet) long fell from the north margin of the growing lava fin or spine sometime during this past weekend. The volume lost was about 50,000 cubic meters (65,000 cubic yards). We think that this event coincided with a large seismic signal recorded at 9:14 pm PDT Sunday night. The volcano was obscured by clouds at that time. The resulting rock-avalanche deposit extends a couple hundred meters (couple hundred yards) to the northeast into a depression formed between the new and old lava domes and the east arm of the glacier. The avalanche was accompanied by an ash cloud that flowed over a broader area. Photographs will be available on our web site tomorrow. Additional smaller rockfalls and avalanches continue.
May 11, 2006:
- 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 broadly northeast at both low and high altitudes early in the day. Later in the day low level-ash clouds would drift northeast, high level ash clouds to the east.
- Recent observations: The volcano is obscured by clouds today. Recent photographs from remote cameras shows that a slab of rock about 70 meters (230 feet) long fell from the north margin of the growing lava fin or spine sometime during the past weekend, probably coincident with a large seismic signal recorded at 9:14 pm PDT Sunday night. The resulting rock-avalanche deposit extends a couple of hundred meters (couple of hundred yards) to the northeast into a depression formed between the new and old lava domes and the east arm of the glacier; an ash cloud accompanying the avalanche left deposits over a broader area . Photographs will be available on our web site later today. Additional smaller rockfalls and avalanches continue.
May 12, 2006:
- 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: The volcano is obscured by clouds this morning, but the weather this weekend looks promising for a visit to the National Volcanic Monument with good viewing conditions. Small rockfalls continue from the growing lava dome following last Sunday night’s major rock avalanche. We’ve received numerous questions about why the seismic signal that accompanied the avalanche isn’t in the list of recent earthquakes and given a magnitude. The answer is that it wasn’t a simple earthquake. It was a complex event with multiple pulses, so it can’t be compared with typical earthquakes.
May 13, 2006:
- 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: The weather this weekend looks promising for a visit to the National Volcanic Monument with good viewing conditions. Small rockfalls continue from the growing lava dome following last Sunday night's major rock avalanche. We've received numerous questions about why the seismic signal that accompanied that avalanche isn't in the list of recent earthquakes and given a magnitude. The answer is that it wasn't a simple earthquake. It was a complex event with multiple pulses, so it can't be compared with typical earthquakes.
May 14, 2006:
- 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 to northeastward.
- Recent observations: The growing lava spine continues to generate rockfalls. Last night, just before 11 pm PDT, one of the larger earthquakes that typically occur once or twice per day was accompanied by a substantial amount of rockfall. An image taken by a remote camera on the crater rim about 20 minutes after the event shows that glowing hot rock debris had been delivered to the talus aprons that flank the steep north and south margins of the spine. Such events are likely accompanied by ash clouds; VolcanoCam images show a small ash cloud produced by a rockfall about 8:30 am PDT this morning.
May 15, 2006:
- 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-northwestward in the morning and north-northeastward later in the day.
- Recent observations: The growing lava spine continues to generate rockfalls. On Saturday night, just before 11 pm PDT, one of the larger earthquakes that typically occur once or twice per day was accompanied by a substantial amount of rockfall. An image taken by a remote camera on the crater rim about 20 minutes after the event shows that glowing hot rock debris had been delivered to the talus aprons that flank the steep north and south margins of the spine. A glow was also detected on satellite imagery monitored by other federal agencies. Rockfall events such as the one on Saturday night are commonly accompanied by ash clouds.
May 16, 2006:
- 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 northwestward.
- Recent observations: The spine in the middle of the lava-dome complex continues to grow, accompanied periodically by rockfalls and moderate-size rock avalanches. Seismicity and motion of the west part of the new dome remain at levels typical of the past few days. Rockfalls and avalanches caused by the growing spine can generate ash clouds that rise above the crater rim.
May 17, 2006:
- 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: The lava spine continues to grow, accompanied periodically by rockfalls and moderate-size rock avalanches. At night incandescence associated with hot rockfalls may be visible. The west part of the new dome continues to deform as fresh lava extrudes from the vent. Seisimicity remains at levels typical of the past few days. Large rockfalls and avalanches caused by the growing spine can generate ash clouds that rise above the crater rim.
May 18, 2006:
- 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: Clear weather today should provide wonderful views into the crater on this 26th anniversary of the 18 May 1980 eruption. The lava spine continues to grow, accompanied periodically by rockfalls, which may generate ash clouds that rise above the crater rim. Seisimicity remains at levels typical of the past few days, with no earthquakes greater than M2.0 in the past 24 hours.
May 19, 2006:
- 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: The lava spine continues to grow, accompanied periodically by rockfalls, which may generate small ash clouds that rise above the crater rim. The rockfalls expose hotter interior portions of the lava dome, which in nighttime images appear as a bright spot or flash. Several bright spots are seen in last night’s images (http://www.luscombe-carter.com/mount_st_helens/), especially around 4:20 am PDT at the time of a vigorous rockfall signal. Seismicity remains at levels typical of the past few days.
May 20, 2006:
- MOUNT ST. HELENS UPDATE 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 northeastward.
- Recent observations: The crater is mostly clear today as seen on the USFS’s VolcanoCam web page, although some weather clouds are drifting around the crater rim and a small steam plume appears to be emanating from the growing lava dome. Lava dome growth continues to be accompanied periodically by rockfalls, some of which may generate small ash clouds that rise above the crater rim. Seismicity remains at levels typical of the past few days, with the largest event (greater than M2.0) in the past 24 hours occurring today around 08:51 a.m. PDT.
May 21, 2006:
- 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 to northward.
- Recent observations: The upper parts of the volcano, including the crater, are partially obscured by clouds today. The lava spine continues to grow, accompanied periodically by rockfalls and moderate-size rock avalanches. Seismicity and motion of the west part of the new dome remain at levels typical of the past few days. Rockfalls and avalanches caused by the growing spine can generate ash clouds that rise above the crater rim.
May 22, 2006:
- 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 northeastward.
- Recent observations: The volcano is obscured today as a weather system moves through the area. The lava spine continues to grow accompanied periodically by rockfalls that can generate small ash clouds that rise above the crater rim. Seismicity at the volcano remains at levels typical of the past several weeks. Two earthquakes, both greater than M6.0 from the Koryakia area and the Kamchatka Peninsula, Russia, are seen on the PNSN volcano and regional webicorders plots at about 04:20 a.m. and 06:16 a.m. PDT, respectively.
May 23, 2006:
- 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 northeastward.
- Recent observations: The volcano is completely obscured by clouds this morning as another weather system moves through the Pacific Northwest. Remote camera views through intermittent breaks in the clouds show that the lava spine continues to grow taller even as its margins crumble. Seismicity at the volcano remains at levels typical of the past several weeks.
May 24, 2006:
- 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 northeastward.
- Recent observations: Once again, the volcano is mostly obscured by clouds as spring rains saturate the Pacific Northwest. Seismicity at the volcano remains at levels typical of the past several weeks as the extrusion of dacite lava continues.
May 25, 2006:
- 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: The upper flanks of the volcano can occasionally be seen peeking through the clouds this morning on the Johnston Ridge Observatory VolcanoCam. Seismicity at the volcano remains at levels typical of the past several weeks with smaller “drumbeat” earthquakes every few minutes and intermittent larger events. An earthquake greater than M2.0 occurred at 7:17 a.m. PDT (1417 UTC). Views from remote crater cameras show continued dome growth and sizeable rockfalls from the actively growing dome.
May 26, 2006:
- 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: The upper flanks of the volcano are receiving fresh snow this morning as another storm system moves through the Northwest, precluding visual observations from remote cameras. Seismicity at the volcano remains at levels typical of the past several months, however the number and magnitude of earthquakes have increased slightly over the past few weeks. This increase is not unusual and is within the realm of seismic activity observed over the past year. An earthquake about M2.9 occurred at 8:48 p.m. PDT (0348 UTC).
May 27, 2006:
- 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 to southwestward early shifting to southeastward by afternoon.
- Recent observations: Clouds preclude visual observations of the volcano this morning. Seismicity at the volcano remains at levels typical of the past few weeks. A magnitude 2.3 earthquake occurred at 3:22 p.m. PDT (2222 UTC) yesterday.
May 28, 2006:
- 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: Once again, clouds completely obscure Mount St. Helens in views from the Johnston Ridge Observatory VolcanoCam. Some clearing is forecast in the coming week?s weather, which may allow for visual observations. Seismicity at the volcano remains at levels typical of the past few weeks.
May 29, 2006:
- 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 to southeastward early shifting to southeastward by afternoon.
- 8:30 a.m. PDT Recent observations: Clouds preclude visual observations of Mount St. Helens this morning. Seismicity at the volcano remains at levels typical of the past few weeks.
- 11:40 a.m. PDT Recent observations: At 9:08 a.m. PDT (1608 UTC) a large rockfall from the growing lava dome corresponded with a magnitude 3.1 earthquake, sending a flow of rock and dust from the new dome. Pilots reported a plume to 16,000 to 20,000 feet. Remote camera views from six minutes after the event showed mostly steam and minor ash plumes in the crater. There is no evidence of an explosion associated with this event. Events such as this are expected during lava dome growth. Weather permitting, scientists will be in the field later this week.
May 30, 2006:
- 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 for a small event or northeastward to eastward for a larger event.
- Recent observations: A crew in the crater this morning reports that yesterday’s large rockfall came mostly from the north side of the growing spine (sometimes called “the fin”), and a smaller amount came from the south side. The rock avalanche resulting from the collapse on the north side flowed down the gully between the 1980-1986 dome and the east arm of the glacier, and partly across the east flank of the 1980-1986 dome. The associated dust cloud flowed farther northward and eastward, but did not extend much beyond the northeast flank of the 1980-1986 dome. Snowmelt from the hot avalanche percolated quickly into the remaining snow pack. Steam and a small amount of dust from the rockfall rose above the crater rim and left a thin deposit on the volcano’s upper northeast flank. Two monitoring instruments on the 1980-1986 dome were damaged by the event and will be replaced. Photos from remote cameras show that extrusion of the spine is continuing.
May 31, 2006:
- 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 north northeastward.
- Recent observations: The volcano is clear and free of visible fuming this morning. Field crews yesterday measured gas emission, did a survey of temperature at the dome, installed 6 global positioning stations on the flanks of the volcano, and examined deposits of Monday’s large rockfall. Gas emission and thermal character of the dome are similar to those measured in recent months. The rockfall on Monday generated an avalanche, now visible from the north as a dark tongue, that came from the east side of the growing spine (sometimes called “the fin”), descended northward around the east side of the 80s dome and down onto the amphitheater floor next to the east arm of the crater glacier. Ash associated with the avalanche lightly dusted the volcano’s upper northeast flank. Seismicity and repeat photographs from remote cameras show that the spine continues to grow. The growing spine is now sufficiently steep and fractured that a rockfall- avalanche similar in size to that of Monday is possible within the next week or so. Such an event could generate an ash plume that would rise above the crater rim and drift downwind.
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