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National Weather Service Operations - Mt. Redoubt

Last updated 08APR09 @ 1800 Images added

Beginning Sunday March 22, 2009 at approximately 22:38 AKDT, Redoubt Volcano produced a series of explosive eruptions that each lasted from four to thirty minutes. These eruptions continue through today and may continue for some time. National Weather Service (NWS) radar, pilot reports, and AVO analysis of satellite imagery suggest that these events produced ash clouds that reached 65,000 ft above sea level (asl), with the bulk of the ash volume between 20 - 30,000 ft asl. Ashfall reports have been received from the Susitna Valley, Kuskokwim Valley, Kenai Peninsula, Matanuska Valley, Anchorage Bowl and as far east as Valdez.

Modified narrative courtesy of the Alaska Volcano Observatory / National Weather Service


Additional images and movies are located the bottom of the page.

For the latest updates on this volcano, please visit the Alaska Volcano Observatory.

The National Weather Service Office in Anchorage supports the Alaska Volcano Observatory, Alaska Aviation Weather Unit, Central Weather Service Unit and Federal Aviation Administration. The common mission among all of these agencies is to protect life and property through the issuance of warnings and forecasts of hazardous weather which empower people to make informed decisions. In the event of a volcanic eruption, the NWS is called upon to confirm the height of the eruption and issue appropriate warnings and advisories for ashfall and flooding. The office utilizes several powerful tools for this analysis within AWIPS (Advanced Weather Interactive Processing System). AWIPS is an interactive computer system that integrates all meteorological and hydrological data, numerical model guidance, as well as satellite imagery and radar data.

A common question asked is how the NWS can determine the altitude of the initial ash plume. The NWS uses a Doppler radar in Kenai to peer into the sky from the ground up. Energy is sent out from the radar and some of this energy bounces off of objects in the sky and returns to the radar. These objects can be rain, snow, hail, insects, birds, terrain and even volcanic ash. Complex algorithms decipher these returns from the radar and give meteorologists an idea of what is in the atmosphere and how high it is. The Anchorage NWS office is in a unique position to provide volcanic ash plume height estimates directly from the Kenai radar due to the close proximity of the radar to Mount Redoubt [roughly 44 miles].

A radar works by rotating around 360 degrees at different elevations to complete a 'scan' (information from all levels) in roughly 5 minutes when in precipitation mode and 10 minutes in clear-air mode. When the Alaska Volcano Observatory raised the alert status from Yellow to Orange in January - the National Weather Service responded by forcing the radar to remain in precipitation mode. This allowed the quickest scans through 65,000 ft for rapid response. The following graphic depiction shows the different elevation slices that the radar has and where it would pass above the volcano. The lowest elevation [0.5 on the graphic] is typically seen on television stations and on our web radar graphic. The lowest two elevations (0.5 and 1.45) actually intersect the volcano below the summit. The 3rd through 12th elevation cuts range from roughly 13,000 ft to 67,000 ft above the radar and give the forecasters a clear view of what the volcano is doing.

A new operational tool that the NWS utilizes is a program that is named 'Four-dimensional Stormcell Investigator (FSI).' This technology allows NWS meteorologists to create and manipulate dynamic cross-sections (both vertical and at constant altitude), to 'slice and dice' storms and view these data in three-dimensions and across time. An example can be seen by clicking on the thumbnail below. This is an FSI image from the morning of March 24th, during the initial phase of the 4th eruption. This was the first eruption to have an ash plume reach an altitude of 65,000 ft. There are four panels within FSI and they represent vertical and horizontal slices through all radar data, constant altitude radar information [e.g. all radar data at 25,000 ft only] and standard elevation slices. The upper right corner of the graphic depicts all radar returns at 43,000 feet. The lower left image shows a vertical cross section through the core of the ash cloud. This allowed for quick analysis of the ash cloud during the initial eruption and throughout the evolution of each ash cloud. The link below shows an animation of the first two eruptions as seen through FSI on the night of March 22nd. These images are screen captures taken by NWS meterologists throughout the eruptions. Note how quickly the ash plume rises and how quickly the heavier material falls out.



Another powerful dataset the NWS utilizes are satellites from across the globe. The data are included within AWIPS from both GOES and POES satellites. Satellites measure the electromagnetic energy at different wavelengths and provide a visual depiction of many different aspects of the sky.Satellites give forecasters the ability to see the world from the top down. , giving them a multitude of information such as night observations when there is no visible light available, ash approximation, wind and precipitation estimates, and many other parameters.

GOES stands for Geostationary Operational Environmental Satellite. It has a geo-synchronous orbit in that it remains over a fixed point on the earth above the equator. In order to do this, the orbit must be 36,000 km above the earth.

  • GOES satellite imagery is also used to estimate rainfall during the thunderstorms and hurricanes for flash flood warnings, as well as estimates snowfall accumulations and overall extent of snow cover. Such data help meteorologists issue winter storm warnings and spring snow melt advisories. Satellite sensors also detect ice fields and map the movements of sea and lake ice.

  • Because there is repeat coverage of the same location on the earth in a matter of 15 - 30 minutes during normal operating conditions, the GOES satellite is ideal for viewing the weather and it's evolution. There are many scales of weather interaction and the GOES satellite provides the opportunity to view starting at the large scale with the full disk down to the mesoscale which we can look at with higher resolution in the visible imagery and coarser resolution in the infrared.

  • In contrast, the POES or Polar-orbiting Operational Environmental Satellites, which does not remain at a fixed point over the earth - it has a sun-synchronous orbit (follows the sun). It operates at a lower altitude of 850 km above the earth.

  • POES microwave instruments observe the earth's atmosphere, clouds, and underlying surface both day and night and in all weather conditions (clouds or no clouds). Some satellite products can detect and monitor volcanic activity. They can even decipher between water clouds and volcanic ash clouds.



  • Webcam Imagery & Loops

    Click on any image to expand - use your left and right keys to navigate


    Webcams
    AVO Webcam Loop from the North Flank of Mt Redoubt during the first daylight eruption on Monday, March 23rd.
    FAA Webcams from Soldotna on March 26th, 2009 from roughly 11:00am to 5:00pm showing the ash falling.
    FAA Webcams from Homer on March 26th, 2009 from roughly 10:00am to 4:00pm showing the ash falling.
    Mt Redoubt Hut Cam
    March 23, 2009
    Homer,AK
    March 26, 2009
    Soldotna, AK
    March 26, 2009
    FAA Webcams from Homer on the morning of April 4th, 2009. Notice how the skies turn pitch black as the ash cloud moves over before depositing ash over the city.
    FAA Webcams from Homer on the morning of April 4th, 2009. Notice how the skies turn pitch black as the ash cloud moves over before depositing ash over the city.
    Homer, AK - View 1
    April 04,2009
    Homer, AK - View 2
    April 04,2009











    Satellite Imagery

    Multi Panel Satellite View
    A large viewing angle from the MTSAT-1R satellite offered a nice depiction of the initial volcanic eruption plume from March 26.

    - Image Courtesy of NOAAs Cooperative Institute for Meteorological Satellite Studies (CIMSS)
    The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASAs Aqua satellite captured this image of the aftermath of the eruption at 2:40 p.m.(March 26), local time, a little more than five hours after the large eruption. A cloud of tan ash extends from the volcano south and east. The ash colors the clouds south of Anchorage.an indication that the volcanic plume rose above the cloud level. A dark-colored streak extends south of the volcano where ash had fallen on the snow. A higher resolution file can be found here [4mb].

    --NASA image by Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center. Caption by Holli Riebeek.
    Multi Satellite Images
    March 26, 2009
    MTSat - Visible Imagery
    March 26, 2009
    MODIS Imagery
    March 26, 2009


    The first eruptions all occurred in darkness, which means that photo-like images from satellites werent possible. But the plumes were detectable in thermal infrared imagery captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASAs Terra (next image) and Aqua (above) satellites. Temperatures range from warmer (black) to colder (white). The Terra MODIS image (next) was captured at 12:30 a.m. March 23, just 16 minutes after the third large eruption. Two plumes of ash are visible: a long white plume reaching north, and a smaller one just northeast the volcano. Communities along the trajectory of the ash plume included Skwenta and Talkeenta. The Aqua MODIS image (above) was captured four hours later, at 4:30 a.m., just as the fifth large eruption began. At that time, the new ash plume was located directly over Mt. Redoubt. Just beneath the plume is a black dot, which is probably heat from the eruption.

    NASA images created by Jesse Allen, using data provided courtesy of the MODIS Rapid Response team. Caption by Rebecca Lindsey.


    The first eruptions all occurred in darkness, which means that photo-like images from satellites werent possible. But the plumes were detectable in thermal infrared imagery captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASAs Terra (above) and Aqua (previous image) satellites. Temperatures range from warmer (black) to colder (white). The Terra MODIS image (above) was captured at 12:30 a.m. March 23, just 16 minutes after the third large eruption. Two plumes of ash are visible: a long white plume reaching north, and a smaller one just northeast the volcano. Communities along the trajectory of the ash plume included Skwenta and Talkeenta. The Aqua MODIS image (previous image) was captured four hours later, at 4:30 a.m., just as the fifth large eruption began. At that time, the new ash plume was located directly over Mt. Redoubt. Just beneath the plume is a black dot, which is probably heat from the eruption.

    NASA images created by Jesse Allen, using data provided courtesy of the MODIS Rapid Response team. Caption by Rebecca Lindsey.


    Aqua - MODIS - Thermal IR
    March 26, 2009
    Terra - MODIS - Thermal IR
    March 26, 2009
    GOES 11 - Visible Imagery
    March 23, 2009
    This is the first of three images showing visibile satellite imagery of an eruption around sunset on March 23, 2009. This image was taken at 0330z on March 24th - or 7:30PM Local on March 23, 2009.
    This is the second of three images showing the sunset eruption as seen from space. The sun angle was low on the horizon and created a shadow that stretched for nearly 150 miles to the east. This image was taken at 0400z on March 24th - or 8:00PM Local on March 23, 2009.
    This is the final image taken at 0430z or 8:30P Local on March 23, 2009. At this point the sun had dropped below the horizen and most visible light was gone.
    NWS AWIPS Terminal - 7:30PM
    March 23, 2009
    NWS AWIPS Terminal - 8:00PM
    March 23, 2009
    NWS AWIPS Terminal - 8:30PM
    March 23, 2009
    High Resolution Picture Transmission (HRPT) Infrared Imagery a few hours following the eruptions in the previous images. The warmer colors signify colder cloud tops.
    This image, acquired by the Formosat-2 satellite on February 10, 2009, shows some signs of current activity, as well as evidence of past eruptions. Redoubt.s 3,108-meter (10,197-foot) summit is near image center, casting a deep shadow on the volcano.s crater. Buried under ice are two lava domes, formed during eruptions in 1966 and 1990. Dark holes in the northward-flowing Drift Glacier were formed where hot magma heated rocks underlying the ice. Crevasses on the steeply dropping glacier are also visible. The 6,000-foot hole is a pit in the snow caused by volcanic activity. On February 26, 2009, the Alaska Volcano Observatory observed a small lahar.an avalanche of volcanic matter.flowing from the 6,000-foot hole.

    Formosat image © 2009 Dr. Cheng-Chien Liu, National Cheng-Kung University, and Dr. An-Ming Wu, National Space Organization, Taiwan. Caption by Robert Simmon.
    Visible Satellite Imagery from the GOES 11 Satellite showing the daylight eruption on March 26, 2009. The ash from this eruption affected areas along the Western Kenai Peninsula through Homer.

    Image Courtesy of NOAAs Cooperative Institute for Meteorological Satellite Studies (CIMSS)
    AWIPS Terminal - HRPT IR
    March 23, 2009
    Formosat 2 - Visible
    February 10, 2009
    GOES 11 - Visible Loop
    March 26, 2009
    Besides volcanic ash, the eruption of Alaskas Mount Redoubt posed another hazard in early April 2009. The volcano.s activity sent lahars.muddy volcanic avalanches.through Drift River Valley, according to the Alaska Volcano Observatory. Because an oil storage facility, the Drift River Oil Terminal, is located in the river valley, a catastrophic lahar could have caused an oil spill.

    On April 4, 2009, the Advanced Land Imager (ALI) on NASA.s Earth Observing-1 satellite captured this image of the Drift River Valley where it connects with Cook Inlet. Lahars have stained the river valley a deep muddy brown. Water channels form branching patterns just west of the Cook Inlet shore, and the dark brown color of each water channel contrasts sharply with the nearby snow. The Drift River Oil Terminal resides in this network of channels, and part of the facility appears as an off-white rectangle in a landscape of meandering mudflows. The same day that ALI acquired this image, the Alaska Volcano Observatory reported that a lahar had developed in the Drift River Valley, as indicated by seismometer readings. Lahars had also been recorded in the Drift River Valley during the previous weeks.

    Full size image can be found here. [4 MB]

    NASA image created by Jesse Allen, using EO-1 ALI data provided courtesy of the NASA EO-1 Team. Caption by Michon Scott.
    Activity at Alaskas Mount Redoubt caused rapid changes on the nearby landscape in early April 2009. This pair of images acquired by the Advanced Land Imager (ALI) on NASA.s Earth Observing-1 satellite shows the area around the volcano on April 1, 2009 (above), and April 4, 2009 (next). These images show the area immediately east of the volcano, between Mount Redoubt and Cook Inlet. (In these images, north is to the right.) In the image acquired on April 1, 2009 (above), nearly the entire area northeast of the volcano is muddy brown, coated with a layer of volcanic ash. The river channel that connects with Cook Inlet is barely discernible given the surrounding ash-covered landscape. A plume from the volcano blows toward the east. Unlike the soft material resulting from burned vegetation, volcanic ash consists of tiny shards of rock and glass. Dangerous to inhale, volcanic ash is also mildly corrosive and able to conduct electricity when wet. Too tough to dissolve in water, this ash can be preserved in snow and ice. Geologists also use ancient volcanic ash layers to calculate the ages of rock strata.

    Full size image can be found here. [4 MB]

    NASA image created by Jesse Allen, using EO-1 ALI data provided courtesy of the NASA EO-1 Team. Caption by Michon Scott.
    Activity at Alaskas Mount Redoubt caused rapid changes on the nearby landscape in early April 2009. This pair of images acquired by the Advanced Land Imager (ALI) on NASA.s Earth Observing-1 satellite shows the area around the volcano on April 1, 2009 (previous), and April 4, 2009 (above). These images show the area immediately east of the volcano, between Mount Redoubt and Cook Inlet. (In these images, north is to the right.) In the image acquired April 4, 2009 (above), a plume still blows toward Cook Inlet, but the landscape has changed. Fresh snowfall has apparently buried the previous coating of volcanic ash. Extending from the volcano (just off the top edge of the image) toward the northeast, the Drift River Valley appears in deep brown, thanks to a recent lahar. South of the river valley, however, a triangular-shaped patch of land now appears brilliant white, thanks to fresh snow. Local snow cover actually preserved a sequence of alternating snow and ash layers in early April 2009, as a picture on the Volcanism Blog shows. Unlike the soft material resulting from burned vegetation, volcanic ash consists of tiny shards of rock and glass. Dangerous to inhale, volcanic ash is also mildly corrosive and able to conduct electricity when wet. Too tough to dissolve in water, this ash can be preserved in snow and ice. Geologists also use ancient volcanic ash layers to calculate the ages of rock strata.

    Full size image can be found here. [4 MB]

    NASA image created by Jesse Allen, using EO-1 ALI data provided courtesy of the NASA EO-1 Team. Caption by Michon Scott.
    Advanced Land Imager - Visible
    April 04,2009
    Advanced Land Imager - Visible
    April 01,2009
    Advanced Land Imager - Visible
    April 04,2009
    Continuing its pattern of heightened activity, Mount Redoubt released a plume of ash, volcanic gases, and steam on April 1, 2009, according to the Alaska Volcano Observatory. Although most emissions remained below an altitude of 4,572 meters (15,000 feet), the plume occasionally reached a height of 7,620 meters (25,000 feet) above sea level. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA.s Terra satellite took this picture the same day. In this image, the plume from Mount Redoubt appears as a translucent beige-gray swath that fans out slightly as it blows across Cook Inlet toward the east-southeast. North of the plume, volcanic ash from recent eruptions has given a gray-brown hue to what was previously a snowy white surface.

    Full size image can be found here. [1 MB]

    NASA image by Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center. Caption by Michon Scott.
    Mount Redoubt experienced another explosive eruption on April 4, 2009, according to the Alaska Volcano Observatory. The eruption sent a cloud of volcanic ash and vapor to a height of roughly 15,240 meters (50,000 feet). The cloud drifted toward the volcano.s southeast. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA.s Terra satellite took this picture on April 4, 2009. Mount Redoubt sits on the western side of Alaska.s Cook Inlet, and the volcanic plume blows toward the southeast, across the water. On the eastern side of Cook Inlet, the plume appears to change direction, moving toward the northeast before resuming its general southeastern course. This zigzag trajectory might be explained by different wind directions at different altitudes. On both the western and eastern sides of Cook Inlet, some of the snowy surface has been colored muddy brown, likely resulting from a coating of volcanic ash.

    Full size image can be found here. [1 MB]

    NASA image by Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center. Caption by Michon Scott.
    Terra - MODIS - Visible Imagery
    April 01,2009
    Terra - MODIS - Visible Imagery
    April 04,2009


    Radar Imagery

    This image shows a loop of the 0.5 degree tilt of the Kenai Radar on the night of the first eruptions. The beam actually intesects the volcano thousands of feet below the summit...but the higher reflectivities are an idea of what fell out of the cloud in the immediate vicinity of the crater.
    This is a static image showing what radar meteorologists call a TBSS - or Three Body Scatter Spike. This spike is likely caused from big pumice balls and rocks causing Mie scattering of the radar energy. This image was from the first eruptions on the night of March 22, 2009.
    These are radar indicated reflectivities from the April 4th eruption. The most interesting detail is seen to the north of volcano in the Drift River Valley. It is believed that those returns follow a lahar moving down the side of the volcano. While those returns are not of the actual lahar...they are that of steam and bits of debris that have been moved into the air. The ash cloud is also seen moving towards the southern tip of the Kenai Peninsula in the lower half of the loop.
    AWIPS Super Res.
    0.5 Tilt Reflectivity Loop
    March 22, 2009
    AWIPS Super Res.
    0.5 Tilt - TBSS
    March 22, 2009
    AWIPS Super Res.
    0.5 Tilt - Reflectivity
    April 04,2009
    These are radar indicated velocities from the April 4th eruption. The most interesting detail is seen to the north of volcano. The green pixels indicated movement towards the radar. It is believed that those returns follow a lahar moving down the side of the volcano. While those returns are not of the actual lahar...they are that of steam and bits of debris that have been moved into the air.
    AWIPS Super Res.
    0.5 Tilt - Velocity
    April 04,2009


    Shea 08APR09



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