|Finding The Fin Before It Finally Falls With A Flourish|
The Cascades Volcano Observatory, operated by the USGS, in Vancouver, Washington, reports the growth of a 300-foot spire projecting out from near the top of the new dome. Called a "fin" by the USGS, this rock projection has been growing as much as five to six feet a day since last November. Similar spires and fins have grown from the new dome, only to eventually collapse. This is a normal occurrence in dome-building.
With the annual reopening of the Johnston Ridge Observatory, the media is again paying attention to Mount St. Helens, especially since the USGS report was issued earlier in the week. We are receiving numerous emails from VolcanoCam viewers asking if it is possible to the new fin using the VolcanoCam.
The answer is yes!! Well, at least until is collapses.
Below are a series of digitally enhanced images created from the above "master" image. We removed some of the image clutter caused by the fine ash on the VolcanoCam's lens window, as well the dust in the air. While the enhanced images should help you to locate the fin in the "live" image, there is nothing quite like a visit to the Johnston Ridge Observatory to see it for yourself!
|Enhanced Image #1 - General View|
In the above false color digitally enhanced image, we digitally removed quite a bit of the dust in the air between the volcano and the camera, as well as the dust on the camera window.
Fine volcanic ash is a regular occurrence here. In early winter before the snows cover the surrounding area, winds swirl the dust over, under, and into everything, including the VolcanoCam. While we endeavour to visit the VolcanoCam during the winter to perform some equipment checks and do a bit of cleaning, winter weather often prevents this from taking place. We only managed two visits to the VolcanoCam during the 2005-2006 winter, one in December and the second one a month later. Hence, the considerable amount of fine volcanic ash partially obscuring the view.
|Enhanced Image #2 - Old Dome Outline|
|The above digitally enhanced image outlines the top of the old dome. This dome grew during a six year period (1980-1986) immediately following the 1980 eruption of Mount St. Helens.|
|Enhanced Image #3 - New Dome Outline|
The above digitally enhanced image outlines the top of the new dome. This dome began with the October 2004 eruption sequence, which is still in progress. The new dome is above and behind the old dome and the south crater wall.
According to the USGS: "The new dome’s summit altitude currently is about 7,550 feet, towering about 400 feet above the 1980s dome as seen from the U.S. Forest Service’s Coldwater visitor center. But that’s still below the 7,770-foot altitude reached last July, before collapse of a previous spine, and well below the crater rim, which is mostly above 8,100 feet except at Shoestring Notch or northward where the crater opens outward toward the roadheads. [March 2, 2006, Daily Update]"
|Enhanced Image #4 - Current Fin Outline|
The above digitally enhanced image outlines the current "fin" or spire projecting upward from the new dome. The USGS reports this fin started growing in November 2005, with a growth rate of five to six feet perday.
It is only a matter of time before the brittle nature of the fin gives way and collapses, as all the other fins and spires that have emerged during this current dome building growth. While there is no way to predict when this will occur, we can only hope it will happen during daylight hours with good, clear weather so the VolcanoCam is able to capture the event.
|Enhanced Image #5|
You may notice the near vertical fuzzy line just above the volcano rim in the upper right-hand quadrant of the image. We've had guesses ranging from an ash plume, a smudge on the camera lens, and a tornado, to that errant Mutant Fly with an extra leg. During our visit to the VolcanoCam in January 2006, we discovered a fine scratch in the glass window of the VolcanoCam case. The scratch is not on the camera lens.
What caused it? That fine volcanic ash can be as sharp as a surgical knife. When blown about by the winds, it is relatively easy for a larger sharp piece to scratch the glass.
Winter weather this past winter was especially fierce, complete with long periods of clouds obscuring any views of the volcano so the scratch was not always visible. Now that the weather is much clearer, it is also much easier to see the scratch. We plan to replace the glass.