2005-01-31

 

USGS Update 2005-Jan-31 09:35

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 today would drift northeast in the morning, shifting to eastward in the afternoon.

Recent observations: Yesterday’s clear skies throughout the region brought good views of a steam plume that drifted lazily upward to above 11,000 ft, about 3,000 ft above the volcano’s rim. The steam is generated almost entirely from the hot rock at the north end of the new lava dome. A small ash-fall deposit was seen mantling new snow on the crater wall and southeast flank. This fallout probably originated by rockfall off the new dome sometime Friday or Saturday. Today, with the mountain fogged in and rain in the forecast, we’re stuck with only instrumental evidence of the eruption. Seismometers record small earthquakes (M<1.5) occurring sporadically beneath the new dome. GPS receivers show continued slow extrusion of the new lava dome.

Update 16:00:The USGS has also updated the Chronology of the Current Eruption.



2005-01-30

 

USGS Update 2005-Jan-30 11:40

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 today would follow variable trajectories with altitude and time. Early in the day, clouds would drift south-southeastward. As the afternoon progresses, winds will shift and clouds would drift weakly northward at low altitudes, but strongly eastward at higher altitudes.

Recent observations: Despite clear skies to the south, the volcano remains mostly obscured by clouds again this morning. It appears that recent snowfall has covered the crater. Seismicity continues at roughly the same rate as that of mid-December. Small earthquakes (M<1.5) occur 2-3 times per minute beneath the new dome. The GPS receiver located on new dome rock continues its remarkably steady east-southeastward progression. GPS receivers on the 1980-86 dome, which lies to the north, continue their trifling northward travel.



2005-01-29

 

USGS Update 2005-Jan-29 09:45

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 today would drift first eastward and then strongly southeastward as the afternoon progresses.

Recent observations: The volcano is mostly obscured by clouds again this morning. Over the past couple of weeks, seismicity has gradually picked up but has now leveled off at a rate similar to that of mid-December. Small earthquakes (M<1.5) occur 2-3 times per minute beneath the new dome. The GPS receiver located on new dome rock continues its remarkably steady east-southeastward progression, having moved about 70 m since installation January 3, an indication that the new lava dome extrudes relentlessly. GPS receivers on the 1980-86 dome, which lies to the north, continue their trifling northward travel, as if the new extrusion is still shoving the old dome northward ever so slightly.



2005-01-28

 

USGS Update 2005-Jan-28 09:50

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 today would drift northward.

Recent observations: The volcano is mostly obscured by clouds again this morning. Over the past couple of weeks, seismicity has gradually picked up and is now back to a level similar to that detected in mid December. Also, GPS stations located on the 1980-1986 lava dome have moved northward about 10-15 cm since early January, following a period of little movement through the latter half of December. We are keeping a close watch to see whether these changes portend a shift in eruptive style or vigor. Next week, if weather permits, crews will attempt more gas measurements, aerial photography, and placement of a new instrumentation package on the rapidly growing part of the new lava dome.



2005-01-27

 

USGS Update 2005-Jan-27 09:10

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 today would drift northeastward, but slightly more northward at low altitudes.

Recent observations: The volcano is again obscured by clouds this morning. Next week, if weather permits, crews will attempt more gas measurements, aerial photography, and perhaps placement of a new instrumentation package on the rapidly growing part of the lava dome.



2005-01-26

 

USGS Update 2005-Jan-26 10:15


Aerial views taken on 2005-Jan-24

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 today would drift west-northwestward to northward.

Recent observations: The volcano is obscured by clouds this morning. Although conditions for the gas-sensing flight on Monday were poor, analysis of data suggests that the emission of sulfur dioxide is about the same as in previous measurements (range of 50 to 250 tons per day). At yesterday’s press briefing there was a lot of interest in gaining better perspective about the size of the uplifted welt and new lava dome. The total volume change represented by the welt and dome as of 3 January of this year is 34 million cubic meters (or 44 million cubic yards). For Portlanders, that is equivalent to 134 Rose Garden arenas. The area of the dome and uplift covers about 60 city blocks. In Portland an equivalent area would extend from the Morrison Bridge to the Hawthorne Bridge and from the Willamette River to the Park Blocks. The top of the new lava dome rises about 550 feet above the pre-eruption surface of the flanking glacier. But the lava dome probably extends to the base of the glacier, which means that its true height is closer to 1100 feet.



 

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2005-01-25

 

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USGS Update 2005-Jan-25 09:30


Aerial views taken on 2005-Jan-23

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 today would drift northward.

Recent observations: Views from the VolcanoCam this morning show a moderate steam plume rising from the west margin of the new lava dome. Strong winds yesterday foiled the gas-sensing flight, but some good photographs were obtained of the new lava dome. A persistent cloud in the western part of the crater created poor conditions for taking vertical aerial photographs for a new digital-elevation model, so that activity was cancelled.



2005-01-24

 

USGS Update 2005-Jan-24 09:20

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 today would drift north-northeastward.

Recent observations: The volcano is clear this morning with only a small steam plume rising off the new lava dome. We plan to have vertical aerial photographs taken today in order to create a new digital elevation model of the crater and new lava dome. We also hope (contingent on availability of a helicopter) to get crews out today to do a gas-sensing flight and take oblique photographs.



2005-01-23

 

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USGS Update 2005-Jan-23 10:30

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 today would drift northward to north-northeastward.

Recent observations: The volcano is visible on the VolcanoCam this morning below high clouds. The crater is clear with only a small steam plume rising off the new lava dome. Since last Sunday’s explosion, the GPS stations on the old lava dome have moved northward several inches and the rate of seismicity has increased slightly. Such changes have been detected in the past and define broad cycles of slightly higher and lower rates of activity.



2005-01-22

 

USGS Update 2005-Jan-22 09:55

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 today would drift northeastward.

Recent observations: The mountain is partly obscured by clouds this morning. When the clouds clear, ash from the explosions on Sunday, January 16, remains visible on the south and east crater walls. No field work is planned for today. Weather permitting, crews will be out next week measuring gas, temperatures on the lava dome, and obtaining new aerial photography. We have no immediate plans to replace the instrumentation damaged by last week’s explosions.



2005-01-21

 

USGS Update 2005-Jan-21 09:20

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 today would drift east-northeastward early in the day and eastward later.

Recent observations: The mountain is generally clear today and emitting a small steam plume. Ash from the explosions on Sunday (January 16) remains visible on the south and east crater walls. No field work is planned for today. Weather permitting, crews will be out next week measuring gas, temperatures on the lava dome, and obtaining new aerial photography.



2005-01-20

 

USGS Update 2005-Jan-20 10:00


Aerial views taken on 2005-Jan-19

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 today would drift northeastward early in the day and eastward later.

Recent observations: Yesterday a crew investigated the effects of an event that occurred about 3 a.m. (PST) on 16 January. Pictures are posted on our web site. The 17-minute-long event was an explosive emission of ash and blocks from the vent area at the north end of the growing lava dome. A shower of ballistic fragments pockmarked a snow-covered area up to several hundred meters northeast of dome with craters up to one meter in diameter. New instruments deployed on 14 January were severely damaged, as was an older GPS instrument. Ash fell thickly in east and west parts of the crater and drifted eastward over the rim depositing a thin layer of gray ash on the east flank outward for at least 3 kilometers. The scale and impact of the explosion was similar to that of 1 October 2004, which was witnessed in clear weather. Analysis of a digital-elevation model made from photographs taken on 3 January provides new information about the size of the growing welt and lava dome. Since last measured on 11 December 2004, the lava dome has maintained its 475-meter length, which is constrained by the old lava dome and crater wall, but has widened from 310 m to 410 m. Its highest point is 7 m higher. The entire welt and dome has increased in volume from 30 to 34 million cubic meters, an average rate of about 2 cubic meters per second. These results suggest that the rate of lava extrusion has decreased from autumn 2004 rates.



2005-01-19

 

USGS Update 2005-Jan-19 08:30


Aerial views taken on 2005-Jan-14

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 today would drift chiefly northeastward.

Recent observations: The volcano is visible on the VolcanoCam this morning and displaying a minor steam plume. Parts of the crater and old dome appear gray and ash covered. We don’t know if it is new ash, perhaps from the ash and steam emission (?) of early Sunday morning, or old ash that has been exposed by extensive snowmelt caused by the recent warm rains. We hope to make a quick aerial reconnaissance today if the weather allows and get close views of the crater and new lava dome.



2005-01-18

 

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USGS Update 2005-Jan-18 10:00

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 today would drift chiefly east-northeastward.

Recent observations: The volcano is obscured by clouds this morning. Data from field sites show that several inches of rain fell yesterday and last night and that streams draining the crater have high water flows. No lahars have been detected. The wet weather outlook for the rest of the week makes field work unlikely. Additional analysis of seismic and other data from about 3 a.m. Sunday morning, when two instruments on and near the new lava dome ceased functioning, suggests that a steam and ash emission occurred, perhaps accompanied by ejection of ballistic fragments. The event lasted about 18 minutes. During that time radio-telemetry signals from a few other instruments in the crater were interrupted temporarily, probably as the result of ash in the air.



2005-01-17

 

USGS Update 2005-Jan-17 10:00

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 today would drift chiefly eastward.

Recent observations: The volcano is obscured by clouds this morning and data from field sites show that it has been raining and streams draining the crater have higher water flows. New instrumentation packages, including video camera, gas sensor, GPS, and seismometer, installed on and near the new lava dome on Friday stopped transmitting data early Sunday morning. The exact cause is not known owing to poor visibility, but interpretation of seismic and other data suggest that a rockfall and perhaps a steam and ash emission generated small flows of ash or falls of rock fragments that damaged the instruments. In the 24 hr prior to the event, the GPS on the north end of the new lava dome moved southward and upward more than 8 meters showing that dome extrusion continues at a vigorous pace. Assessment of conditions in the crater awaits improved visibility.



2005-01-16

 

USGS Update 2005-Jan-16 09:25

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 today would chiefly drift west-northwestward.

Recent observations: The volcano is shrouded in clouds this morning. New instrumentation packages installed on the dome Friday are transmitting data that will be used to more closely track movement of the north end of the new dome. Seismicity suggests that small rockfalls are occurring from the dome. Such rockfalls may generate ash plumes that drift over the crater rim.



2005-01-15

 

USGS Update 2005-Jan-15 11:00

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 today would drift westward at low altitude and eastward at higher altitudes early, becoming northward at low altitude and northeastward at higher altitudes later in the day.

Recent observations: Field crews had a successful day in the field yesterday. An instrument package containing a video camera and gas sensor was installed between the new and old lava domes and will send back a scene every five minutes of the north end of the new lava dome, which is the end at which lava is actively extruding. A “spyder” containing a GPS unit and a seismometer was slung by helicopter onto the north end of the new lava dome. The spyder was visible on the video images. Both packages will aid us in closely tracking the movement and growth of the new lava dome and in better understanding seismic signals. Geologists also collected new rock and ash samples and technicians serviced one of the seismic stations on the outer flanks. The dome continues to grow and fracture. A large slab on the west side of the dome had collapsed recently and had generated a small rock avalanche and ash cloud that had drifted over the south crater rim. A bright glow on the VolcanoCam seen Thursday night was likely caused by this event.



2005-01-14

 

USGS Update 2005-Jan-14 10:00

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 today would drift southeastward, although low altitude winds would carry some ash westward.

Recent observations: The volcano is clear this morning, and crews are in the field. If wind conditions permit, we will install two instrument packages on and near the new lava dome. A GPS and seismometer on the new lava dome and a video camera and gas sensor between the new and old lava domes. We will also make visual and thermal-sensing observations and service a seismic station. The existing GPS “spyder” on the southeast part of the new lava dome continues to move southeastward about 2 meters per day.



2005-01-13

 

USGS Update 2005-Jan-13 09:15

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 today would drift southeastward.

Recent observations: The volcano is obscured by clouds this morning, but the weather should improve for tomorrow’s field work. If wind conditions permit, we plan to install two instrument packages on and near the new lava dome. These were described in yesterday’s update.



2005-01-12

 

USGS Update 2005-Jan-12 10:00

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 today would drift east-southeastward.

Recent observations: The volcano is obscured by clouds today. Weather permitting on Friday, we plan to install two instrument packages on and near the new lava dome. A package on the northeast portion of the uplifted area between the new and old lava domes will contain a video camera and gas sensor. The video camera will provide detailed information on rates and patterns of dome growth and the gas sensor will provide real-time information on volcanic-gas concentrations in the air near the dome. The other package will be installed on the north end of the new lava dome. It will contain a GPS unit and a seismometer. The aim of both installations is to obtain data that will help us to correlate dome movements and seismicity so that we can better understand the process of dome extrusion.



2005-01-11

 

USGS Update 2005-Jan-11 10:50

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 today would drift southward early and southeastward drift later in the day.

Recent observations: The VolcanoCam shows a weak steam steam plume rising above the new lava dome and drifting over the southeast crater rim. Brief aerial views yesterday around midday showed considerable steaming from the south end of the new dome. Evidently hot rock had gotten in contact with uplifted and fractured glacier ice causing melting and steam production. Glimpses of the new lava dome suggested continuing extrusion at its north end.



2005-01-10

 

USGS Update 2005-Jan-10 09:50

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 today would drift northeastward early and then switch to an eastward drift later in the day.

Recent observations: The mountain is clear today and emitting a moderate steam plume. Seismicity and deformation of the south part of the lava dome are proceeding at rates similar to those in the recent past. Digital analysis of recent aerial photography suggests that the overall rate of dome growth may have slowed down since late November. Later this week, field crews plan to install more GPS units near the vent area to measure extrusion rate.



2005-01-09

 

USGS Update 2005-Jan-09 09:00

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 today would drift east-northeastward.

Recent observations: Views of the volcano are still obscured by clouds. Seismicity and ground deformation are proceeding at rates similar to those in the recent past. Consequently we infer that the rate of lava-dome extrusion continues unchanged.



2005-01-08

 

USGS Update 2005-Jan-08 11:00

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 today would drift northeastward.

Recent observations: Views of the volcano are still obscured by stormy weather. Seismicity and ground deformation are proceeding at rates similar to those in the recent past. Consequently we infer that the rate of lava-dome extrusion continues unchanged.



2005-01-07

 

USGS Update 2005-Jan-07 10:30

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 today would drift northeastward early in the day and north-northeastward later.

Recent observations: The volcano is still obscured by a snowstorm. Seismicity and ground deformation are proceeding at rates similar to those in the recent past. Consequently we infer that the rate of lava-dome extrusion continues unchanged.



2005-01-06

 

USGS Update 2005-Jan-06 09:25

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 today would drift southward early in the day then switch to an eastward drift by late afternoon.

Recent observations: The mountain is obscured by clouds from a storm that has settled into the region. Several inches of snow are expected to accumulate at the mountain over the next few days. Seismometers indicate that seismicity continues at a very low level, and the GPS unit on the rear of the lava dome continues to move slowly outward and downward. Crews will be back in the field during the next significant break in weather to install more GPS units.



2005-01-05

 

USGS Update 2005-Jan-05 09:55

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 today would drift west-southwestward.

Recent observations: A communications malfunction with the VolcanoCam prevents remote views of the volcano this morning. From town, however, the volcano is clear. Seismicity continues at a very low level interspersed with a few quakes per day as large as about magnitude 1.5. Analysis of photographs shows that the north end of the lava dome continues to emerge from the vent at a rate similar to that observed over the past several weeks, and that movement of this part of the dome is somewhat decoupled from the fractured bulk of the dome farther to the south. As a result, different parts of the dome are moving and shifting at different rates. We have no specific field plans for the next several days. When we next go out, crews plan to deploy another GPS unit on the rapidly emerging part of the dome near the vent.



2005-01-04

 

USGS Update 2005-Jan-04 09:10


Aerial views taken on 2005-Jan-03

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 today would drift west-southwestward.

Recent observations: The volcano is very clear without a steam plume, but winds are very high. Seismicity continues at a very low level. We had a very successful field day yesterday. Crews placed a GPS unit on the southeast side of the new dome, measured gases, and collected rock samples. Preliminary GPS data show that expansion of the rear part of the dome has slowed to a rate of only a few meters per day. However, observations reveal that the new dome is heavily fractured and faulted; the north end emerging from the vent remains smooth and appears to still be moving relatively rapidly. Measured gases were not significantly different than previous measurements. Rock samples from the new dome are being analyzed. We have no specific field plans for the next several days.

Update: 17:00

Added link to photos



2005-01-03

 

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USGS Update 2005-Jan-03 08:45

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 today would drift south-southwestward.

Recent observations: The volcano is clear and emitting a modest steam plume. Seismicity continues at a very low level. Recent views of the new dome reveal that it is becoming heavily broken and shedding minor rockfalls that cause modest ash plumes. Today, crews will attempt to deploy a GPS unit on the new dome, make visual observations, and measure gases.



2005-01-02

 

USGS Update 2005-Jan-02 09:50

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 today would drift westward at low elevations and west-southwestward at high elevations early in the day and west-southwestward at all elevations later.

Recent observations: Views of the volcano from the VolcanoCam show the crater is partly obscured by clouds and steam. Seismicity continues at a very low level. Clear weather forecasted for next several days will hopefully provide an opportunity for visual investigations and slinging of GPS instruments onto the new lava dome.



2005-01-01

 

USGS Update 2005-Jan-01 10:50

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 today would drift northward early in the day and northwestward later.

Recent observations: Views of the volcano from the VolcanoCam are again obscured by clouds and the DomeCam is covered with ice. The level of seismicity continues at a very low level. Clear weather forecasted for early next week will hopefully provide an opportunity for visual investigations and slinging of GPS instruments onto the new lava dome.



Standard USGS Update

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, episodic changes in the level of activity can occur over days to months. The eruption could also 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.

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.

The U.S. Geological Survey and the University of Washington continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.

My intent with this page is to provide a clearning house for links to the current activity at Mt.St.Helens. Please send me any links of interest that you may come across, whether for permanent sites or for news reports. I'm not going to be able to do this all alone and all help will be appreciated.

(Disclaimer— I have no association with anyone or any organization, and speak only for myself. Links and quotes are provided for information only.)

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