For the third time, the meteorological observatory on Mt. Hoher Sonnblick (3106m) in the Hohe Tauern mountains registrated St.Elmo´s Fire on its webcams (2–3). But contrary to the two preceding cases (1–2), this time St. Elmo´s Fire occurred during a thunderstorm, the nearest lightnings of which were about 600 metres away. While St. Elmo´s Fire appeared, the intensity of the electric field increased from -3000 up to +8000 V/m (unfortunately no diagram available). At the same time, snowfall was recorded at temperatures of -2°C.
The webcam which recorded St. Elmo´s Fire is located on a ridge between Mt. Goldbergspitze and Mt. Roter Mann at about 2970 metres above sea level looking northeast. On the right Mt. Goldbergspitze can be seen, and in the centre of the picture there is the Kleinfleißkees wit Mt. Hoher Sonnblick. The highest mountain on the left is Mt. Hocharn (3254m). The camera is part of a glaciological research programme around the Sonnblick-observatory. Its purpose is to provide data about the snow cover of the Kleinfleißkees and is operated by the ZAMG (Zentralanstalt für Meteorologie und Geodynamik – Central Institution for Meteorology and Geodynamics).
Last night the webcam of foto-webcam.eu registered on Mt. Hoher Sonnblick (3106m, Hohe Tauern, Austria) stunningly St. Elmo’s fire again. And as in the first case, the small purple flames were not caused by thunderstorms, but by a combination of heavy snowfall and wind.
The diagrams show the measured field strength in conjunction with the fallen precipitation which is completely fallen as snow.
A time-lapse recordings of different webcam shows the unusual length of the St. Elmo´s Fire.
Thanks to Hermann Scheer from the Meteorological Observatory Hoher Sonnblick, Austria for the interesting material.
On November 28, the webcam of the Meteorological Observatory on the 3106 metres high Mt. Hoher Sonnblick in the Hohe Tauern Mountains in Austria could catch this unbelievable St. Elmo´s Fire. This photographic webcam, a Canon EOS 1100D, was installed by radio hams and takes one picture every 10 minutes.
Weather observer Hermann Scheer describes the meteorological situation as follows: “The day the pictures were taken ist was snowing, and there was a stormy southwesterly wind with wind speeds around 60 kph. There was no thunderstorm near. I did not notice any discharges, but I could clearly hear the crackling noise on the tower outside, which is always a sign that there is a certain voltage applied. When I went to the platform with my camera the first time, I could not catch St. Elmo´s Fire quite clearly and did not really notice how strong it was. Later, during the second photo shooting, the camera on the tripod began to sparkle, and I also noticed the tension in my short hair. Then I saw St.Elmo´s Fire on the suntracker. The interesting phenomenon lasted for about one hour.”
A high field strength under conditions with falling snow and strong wind is not very rare, as these example diagrams from a day with similar weather conditions show (1–2). When there is enough tension generated by wind friction and high humidity, an electric current begins to flow between the charged air and the point of the instrument. The air becomes ionized generating a flickering, pale blue light that looks like a flame. St. Elmo´s Fire is probably reported so rarely because only very few people look for it on mountain tops under such weather conditions, and during thunderstorms there are no people there.
But even if St. Elmo´s Fire is very beautiful to see, it is in any case a warning. If you see St. Elmo´s Fire near, it is probably a hint that a discharge is imminent. So, if you see it, you should look for shelter immediately.
On Nov/14/2007 between 18:00 and 19:00 CET St. Elmo’s fire appeared on a tower at the summit of Mt. Gäbris in Switzerland. The phenomenon was captured with a high sensitive video camera operated by Mark Vornhusen of Meteomedia, a private weather company.
The St. Elmo’s fire developed during a snow thunderstorm. Only one lightning strike occurred during this storm. The strike is visible on the webcam images at 18:55 CET as a sudden flare of the image and was heard by the author, who lives 2km away from the summit. The lightning strike was not close to the tower, because the flare was not very bright. The cameras operate with a special software that is able to capture all bright objects on the night sky, even if the duration is only a fraction of a second (lightning, meteors).
The St. Elmo’s fire was first visible on the webcam images at 18:05 CET and lasted about two minutes. The second and most intense appearance occurred between 18:40 and 18:50 CET, followed by the lightning strike at 18:55. During the 10 minute interval between 18:40 and 18:50 CET the weather station, which is also located on top of the tower, measured a wind gust of 75 m/s (270 km/h). This is obviously not a real wind speed. More likely it is an interference of the high voltage and the St. Elmo’s fire to the anemometer. The ultrasonic anemometer uses sound speed to measure the wind speed (http://thiesclima.de/usanemo.htm).
Author: Mark Vornhusen, Gais, Switzerland