Lightning Videos
Mt Cleveland
Mt Redoubt


Mount Redoubt

This page contains links to NexStorm screen capture videos associated with the Mt. Redoubt eruptions starting March 22, 2009. See bottom of this page for location map or go to Alaska Volcano Observatory for additional details of volcanic activity at Mt. Redoubt and other volcanoes in Alaska.

The focus point of all videos is our station in Anchorage, AK, and all dates and times are local (Alaska Daylight Time or Alaska Standard Time).  Mt. Redoubt is located 170 km southwest of our station. In the videos, Mt. Redoubt is located just above the 200 km range ring near the western shore of Cook Inlet.

Viewer Notes: The Mt. Redoubt lightning activity is recorded as occurring southwest to west of our station. In some cases, the distance and direction accuracy appears to be poor. Possible reasons for the inaccuracies are:

  • The electromagnetic pulses associated with the lightning may be reflected by the mountains and we may be recording multiple instances of the same events
  • The events are aliased during processing
  • The processor is calibrated on regular thunderstorm lightning and volcanic lightning may have different characteristics, making distance calculations inaccurate

We have been unable to confirm or to compare our results with other lightning detection networks that may be operating in Alaska (if any). A free version of NexStorm, NexStormLite, can be used to replay the original NexStorm files (contact us for file availability).

Watch Videos:  Click on links below for indicated file format (dates and times are local). 

Time (local)

Time Compression AVI format (compressed) WMV format Speed X real time Notes

March  22, 2009

1 h/1 min

0.8 MB

3.3 MB



March 23, 2009

6.5 h/15 min

5.5 MB

39.3 MB



March 23, 2009

2 h/5 min

1.7 MB

11.8 MB



March 27, 2009

2.5 h/2 min

0.8 MB

3.9 MB



March 27, 2009

2.0 h/1 min

1.3 MB

3.9 MB



March 27, 2009

3.5 h/2 min

2.5 MB

7.0 MB



March 27, 2009

1.0 h/0.5 min

0.9 MB

2.1 MB



March 28, 2009

1.0 h/15 min

2.9 MB

36.8 MB



March 28, 2009

0.5 h/2 min

1.0 MB

5.1 MB



March 28, 2009

1.0 h/4 min

1.2 MB

9.6 MB



Notes to above table:

1. This video shows some activity occurring around 600 - 800 km southeast of our station in the Gulf of Alaska/North Pacific Ocean. This is from a nearby noise source and is unrelated to the volcanic lightning activity.

Symbols: The table below shows strike symbols (this information also is shown in the lower-left corner of the video image). 

[New Strikes - Red] [Old Strikes - Yellow/Orange]
Δ + x

After 60 s, a "new" strike changes to an "old" strike. New strikes have a real time display persistence of 60 s, so they quickly flash on the above screen playbacks; old strikes have a persistence of 60 minutes and last longer. When a large dotted diamond target appears, the number of strikes in the area has reached a certain storm intensity. The diamond color changes from yellow to orange to red to indicate relative intensity.

Video Capture data:

Creative Softworx Capture Professional V6.05 was used to capture the playbacks and to save them in the AVI file format.  Applian Technologies WMCapture V3.1 was used to capture the playbacks and save them in the WMV file format. Playbacks were speeded up to allow screen captures spanning one to several hours to be played back in a few minutes.   


  • Frame rate: 10 f/s
  • File Type: AVI
  • Compressor: Microsoft Video 1
  • Temporal Quality Ratio: 0.75
  • Image format: 16-bit
  • Dithering if necessary: Yes
  • Quality: 75
  • Key frame rate: 15

AVI videos have been tested on Windows Media Player 11 and Nero ShowTime 4 but may be viewed on any player that supports the AVI format with the indicated compressor.


  • Video bandwidth: 1200 kb/s
  • Frame rate: 25 f/s

Public domain image courtesy of AVO/ADGGS; Image Creator: Janet Schaefer; http://www.avo.alaska.edu/image.php?id=15524

Public domain image courtesy of the Alaska Volcano Observatory : http://www.avo.alaska.edu/image.php?id=14033

Public domain photograph of Redoubt, as seen from near Homer AK on April 11, 2009. Photograph courtesy of Turea "Midge" Grice.  http://www.avo.alaska.edu/image.php?id=18029

NexStorm and NexStormLite are trademarks of Astrogenic Systems.