2004-12-31

 

USGS Update 2004-Dec-31 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, with low altitude clouds moving northwestward and high altitude clouds moving northeastward.

Recent observations: Views of the crater are obscured by clouds. The level of seismicity has remained at a very low level for the past few days. Directions and rates of movement of GPS stations on the old lava dome and growing welt around the new lava dome appear not to have changed during this same time period. The significance, if any, of this low level of seismicity remains to be seen.



2004-12-30

 

USGS Update 2004-Dec-30 09:20


Aerial views taken on 2004-Dec-28

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-northwestward early in the day and north-northeastward later.

Recent observations: Views of the volcano are obscured by clouds and the outlook over the next few days is for snow. The level of seismicity has declined very slowly over the past few days is at its lowest level since dome building began in October. The significance, if any, of this low level remains to be seen.



2004-12-29

 

USGS Update 2004-Dec-29 10:45

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 northward.

Recent observations: Yesterday field crews were able to get good thermal and photographic observations of the growing lava dome. These coupled with views from the DomeCam show clearly that the northern part of the new lava dome is being pushed upward onto the southern part along the prominent fractures created during the past two weeks. Concurrently, the east and west sides of the dome have been moving outward. All these changes are in response to continuing extrusion of lava into the dome. A result of dome expansion toward the east and west is a slight (one inch or less) outward movement of GPS instruments on the outer east and west flanks of the volcano. Similar movements were detected one month ago on the south side when the lava dome reached the base of the south crater wall. All are expectable and are not cause for any alarm. Difficult wind conditions and shifting steam plumes made delivery of new Spiders (portable GPS stations) onto the dome impossible. Deteriorating weather conditions in the afternoon interfered with the planned gas-sensing flight.



2004-12-28

 

USGS Update 2004-Dec-28 08:20


Aerial views taken on 2004-Dec-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 northwestward.

Recent observations: The view from the VolcanoCam this morning is clear and there is no steam in the crater. Today, field crews plan to measure gas, thermally image the lava dome, install new GPS, and collect rock samples.



2004-12-27

 

USGS Update 2004-Dec-27 08:55

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 north-northwestward early in the day, and switch to a more northwestward drift later in the day.

Recent observations: Field instruments indicate that the lave dome continues to grow at a rapid rate. The view from the VolcanoCam this morning shows the crater partly filled with clouds and steam. If the weather improves sufficiently, we may attempt to obtain new aerial photographs of the lava dome. Otherwise, we have no field plans for today. If weather permits, field crews plan to measure gas, install new GPS, take new photographs, and collect a rock sample later in the week.



2004-12-26

 

USGS Update 2004-Dec-26 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 northeastward.

Recent observations: Clouds and icicles obscure views from the VolcanoCam this morning. Those who check Mount St. Helens’ seismicity on the PNSN Webicorders will note that late yesterday afternoon’s M8.9 earthquake in Sumatra, although well recorded on many PNSN stations, doesn’t show up prominently on the stations close to Mount St. Helens. That is because seismologists set the sensitivity of St. Helens’ stations low so that they will stay on scale and record the ongoing small earthquakes that are close to many of the stations.



2004-12-25

 

USGS Update 2004-Dec-25 10:45

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 northeastward.

Recent observations: Views of the volcano from the VolcanoCam are obscured by clouds this morning. Photographs taken during field work on Thursday show portions of the eastern side of the new lava dome that were intermittently visible amongst clouds of water vapor that covered most of the dome. The formerly smooth surface of the east side is cracking as the dome expands. Rockslides are being shed from the crumbling surface but none have consisted of material hot enough to generate pyroclastic flows or ash clouds.



2004-12-24

 

USGS Update 2004-Dec-24 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 southeastward early in the day and northeastward later.

Recent observations: The VolcanoCam is again providing clear views of the volcano this morning. A moderate steam plume is rising from the new lava dome and drifting over the south rim of the crater. Yesterday field crews serviced several seismic stations and completed repairs to a key radio transmitter. They were successful in retrieving one of the Spiders (a portable seismic and GPS station slung into place by helicopter) from the old lava dome and replacing it with a newer version. The new lava dome was too steamy to permit placement of a new Spider there or to obtain clear photographs.



2004-12-23

 

USGS Update 2004-Dec-23 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 southward.

Recent observations: The VolcanoCam is providing clear views of the volcano this morning and there should be good views from the lowlands once the fog lifts. A moderate steam plume is rising from the new lava dome and drifting over the south rim of the crater. Field crews are on their way to service seismic stations and to complete repairs to a key radio transmitter. They will also attempt to retrieve one of the Spiders (a portable seismic and GPS station that was slung into place by helicopter) from the old lava dome and replace it with a newer version.



2004-12-22

 

USGS Update 2004-Dec-22 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 south-southeastward early and transition to a more southward drift later.

Recent observations: Though valleys are clouded, the mountain is partly clear today and sports a strong steam plume. Clear weather is forecast for the next few days. Tomorrow, field crews plan to service seismic stations, continue repairs to radio transmitters, and install GPS units. Further analysis of last week’s gas measurements shows that SO2, CO2, and H2S are well within the range of previous measurements; there has been no significant change in emissions. Analyses of recent aerial photographs and lidar surveys are underway and updated estimates of dome volume will be forthcoming.



2004-12-21

 

Latest News Reports



 

USGS Update 2004-Dec-21 08:55

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 south-southeastward.

Recent observations: Clouds again obscure the mountain, but better weather is forecast for later in the week. According to field sensors, there is no significant change in the eruptive activity. When the weather improves, field crews will service seismic stations, continue repairs to radio transmitters, and install more GPS units. Preliminary analyses from a gas-sensing flight last week suggest that emissions of SO2 may be slightly elevated, but within the range of past measurements; confirmation of results awaits further analysis. As of the end of November, the “whaleback” measured about 500 m long, about 200 m wide, and its highest point, which extends above the old lava dome, reached about 275 m above the old crater floor. The volumetric change associated with emplacement of new lava (the new dome, uplift, and glacier deformation) was about 28 million cubic meters. The old lava dome, which grew from 1980-86, has a volume of about 80 million cubic meters.



2004-12-20

 

USGS Update 2004-Dec-20 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 southeastward early in the day, and more south-southeastward later in the day.

Recent observations: Morning clouds again obscure the mountain, but our field sensors indicate no significant change of activity. The recent swarm of large earthquakes (about magnitude 3) has diminished. A few large quakes (up to about M2.3) occurred overnight amidst the ongoing pattern of frequent smaller earthquakes, but the size and frequency of those larger quakes has declined. Data from the gas-sensing flight last Friday are still being processed. No field work is planned for today.



2004-12-19

 

USGS Update 2004-Dec-19 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 north-northeastward early in the day, and swing southeastward later in the day.

Recent observations: This morning, clouds obscure the mountain, and no field work is planned for today. Overnight a few more earthquakes of about magnitude 2.5-3 occurred amidst the ongoing pattern of frequent smaller earthquakes. Such swarms have occurred on several occasions during the past month and are not unusual given the nature of the eruption. Results from the gas-sensing flight on Friday are still being processed and will be made available once processing is complete.



2004-12-18

 

USGS Update 2004-Dec-18 10:30


Aerial views taken on 2004-Dec-16

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 early in the day. Later in the day, ash clouds would drift northward at low altitude and eastward at higher altitude.

Recent observations: This morning, a white vapor plume is again visible rising above the crater rim and drifting off southward. The gas-sensing flight cancelled by Thursday’s conditions took place yesterday. Results should be available in the update tomorrow or Monday. No field work is planned for the weekend. Similar to Thursday night, three more earthquakes of magnitude 2.7 to 3.1 occurred last night amidst the ongoing pattern of frequent smaller earthquakes. Such swarms have occurred on several occasions during the past month.



2004-12-17

 

USGS Update 2004-Dec-17 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 east-southeastward.

Recent observations: We got clear views of the crater mid-day yesterday during a thermal-imaging flight. The new dome has noticeably broadened and the prominent fracture system along its top continues to widen. Hot cracks emit ash intermittently. During the night of December 15 (Wednesday) ash emitted from the east side of the dome formed a cloud that swept down the east arm of the glacier and over east side of the old lava dome, leaving a dark smear of ash on the snow on its north face. This smear is visible on the USFS VolcanoCam. The flow was relatively cool as it did not melt much snow. We were also able to repair an important radio-telemetry site that was severely damaged during the recent windstorm and do other needed maintenance. Owing to a late start caused by lingering fog in the metro area, we were not able to fit in a gas-sensing flight. That flight will begin shortly today. This morning the volcano is emitting a vapor plume that is drifting over the southeast crater rim. Four earthquakes of about magnitude 3 occurred overnight amidst the ongoing pattern of frequent smaller earthquakes. Swarms of similar-sized events have occurred on several occasions during the past month.



2004-12-16

 

USGS Update 2004-Dec-16 08:25

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 southeastward early in the day and east-southeastward later.

Recent observations: The mountain is clear today, but the lowlands are blanketed with light fog. We are planning a full day’s work today, and hope to have crews in the field by mid morning. Strong overnight glow on the volcano-cam and data from our field instruments suggest that relatively steady-state dome growth continues.



2004-12-15

 

USGS Update 2004-Dec-15 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 southeastward early in the day and east-southeastward later.

Recent observations: The mountain is clear today, but a heavy blanket of lowland fog prevents flights from leaving town. As a result, crews will not be in the field today. We are planning a full day’s work tomorrow, unless fog inhibits flying. Data from our field instruments suggest that relatively steady-state dome growth continues.



2004-12-14

 

USGS Update 2004-Dec-14 09:30


Aerial views taken on 2004-Dec-11

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 to east-southeastward later.

Recent observations: No field work is planned for today, but we are planning a full day’s work on either Wednesday or Thursday of this week. Data from instruments in the field suggest that relatively steady-state dome growth continues.



2004-12-13

 

USGS Update 2004-Dec-13 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 northward early in the day and northeastward later.

Recent observations: No field work is planned for today, but we hope to get out later this week if the weather improves, as forecast.



2004-12-12

 

USGS Update 2004-Dec-12 10:30

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 altitudes and northeastward at higher altitudes early in the day and northward at all altitudes later.

Recent observations: Aerial views of the crater yesterday show that the new lava dome is becoming increasingly fractured as a new, but as yet ambiguous, pattern of growth begins to emerge. The new pattern should become clearer over the next several days. No field work is planned for today.



2004-12-11

 

USGS Update 2004-Dec-11 09:30

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: The volcano is partly visible this morning on the VolcanoCam and is clearly visible from the Portland metropolitan area. No steam plume is evident. Overnight rainfall increased stream flows, but the acoustic flow monitors recorded no lahars. No field work is planned for today.



2004-12-10

 

USGS Update 2004-Dec-10 08:45

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: Poor weather continues to prevent good observations and no field work is planned for today.



2004-12-09

 

USGS Update 2004-Dec-09 09:30

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 eastward.

Recent observations: Storm effects on field-sensor signals have abated and high-quality data are flowing again. The ongoing sequence of small (mostly less than M1.5) earthquakes continues. Poor weather continues to prevent good observations and field work, and no field work is planned for today. When weather permits, field crews will conduct visual and hydrological observations, replace and maintain seismic equipment, attempt gas and thermal-imaging measurements, and install additional GPS stations.



2004-12-08

 

USGS Update 2004-Dec-08 10:05

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 in the day.

Recent observations: High wind, rain, and snow from a large storm are wreaking havoc with field-sensor telemetry. Some seismic stations show considerable noise, and some signals are temporarily dropping out. The ongoing sequence of small (mostly less than M1.5) earthquakes continues, and no new large (>M2.5) quakes have been recorded within the past 24 hours. A single GPS station high on the outer southeast flank of the volcano (~7300 feet) shows about 2 cm (1 inch) of progressive southeastward movement over the past 3 weeks. This minimal movement, apparently in response to new lava impinging on the southeast crater wall, is an expected consequence of the nature of the dome growth occurring in the crater. Additional station installations are planned for the outer south flank to determine the extent of the area responding to the lateral load. Poor weather has prevented recent observations and field work, and no field work is planned for today. When weather permits, field crews will conduct visual and hydrological observations, replace and maintain seismic equipment, attempt gas and thermal-imaging measurements, and install additional GPS stations.



2004-12-07

 

USGS Update 2004-Dec-07 09:50

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 in the day.

Recent observations: Within the past 24 hours, two large (about M2.5-3) earthquakes occurred amidst the ongoing sequence of smaller (mostly less than M1.5) earthquakes. These earthquakes are similar to other large quakes that have occurred episodically over the past several weeks, and represent nothing unusual in the expected sequence of events accompanying lava-dome growth. No field work was undertaken yesterday and none is planned today. Poor weather has prevented recent observations and field work. In the coming days, field crews will conduct visual and hydrological observations, replace and maintain seismic equipment, and attempt gas and thermal-imaging measurements as weather permits.



2004-12-06

 

USGS Update 2004-Dec-06 09:20

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: Overnight, three large earthquakes of about magnitude 3 occurred amidst the ongoing sequence of smaller (mostly less than M1.5) earthquakes. This mini-burst of large earthquakes is similar to others that have occurred episodically in the past several weeks. Such a pattern represents nothing unusual in the expected sequence of events accompanying lava-dome growth. No field work was undertaken yesterday and none is planned today. In the coming days, field crews will conduct visual and hydrological observations, replacement and maintenance of seismic equipment, and gas and thermal-imaging measurements as weather permits.



2004-12-05

 

USGS Update 2004-Dec-05 10:10

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, then switch to east-southeastward later in the day.

Recent observations: No field work was undertaken yesterday and none is planned today. In the coming days, field crews will conduct visual and hydrological observations, replacement and maintenance of seismic equipment, and gas and thermal measurements as weather permits.



2004-12-04

 

USGS Update 2004-Dec-04 10:15

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: No field work was undertaken yesterday and none is planned during the weekend.



2004-12-03

 

USGS Update 2004-Dec-03 08:50

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 to eastward later in the day.

Recent observations: A steam plume rising from the new dome inhibited significant visual observations yesterday, and adverse winds inhibited successful measurements of gases. Other crews spent time updating and hardening hydrological field instrumentation. The volcano is clear and again sporting a steam plume that rises above the south crater rim. However, there are no plans for field work today.



2004-12-02

 

USGS Update 2004-Dec-02 09:45

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.

Recent observations: The volcano is clear and sporting a steam plume that rises above the south crater rim. Once the low fog clears, field crews plan visual and hydrologic observations, a gas-sensing flight, and maintenance of several instruments.



2004-12-01

 

Latest News Reports



 

USGS Update 2004-Dec-01 10:05

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise high above the crater rim today would drift south-southeastward early in the day and southward later.

Recent observations: No field work was possible yesterday. Weather permitting, crews will be in the field tomorrow doing instrument maintenance and making some hydrologic measurements. From photographs taken on Monday, we now know that the GPS instrument, or Spider, that had been riding along on the new lava dome since November 20 is lost. The crumbling southwest margin of the dome probably neared the Spider on Saturday, radio communications became intermittent, and were lost on Sunday when the Spider evidently fell off the cliff into the talus below. In its week-long journey it moved about 75 meters (250 feet) south-southeastward and about 8 meters (26 feet) upward. Future deployments of new Spiders are being considered.



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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