Saint Helens

先日、シアトルに住むホストマザー Judy に近況を報告する写真を送ったところ、お返しに、セント・へレンズ山（Mt. St. Helens）の綺麗な写真が転送されてきました。

セント・へレンズ山は標高2975mで、米国ワシントン州南部にある活火山。1980年5月18日に大噴火しましたが、噴火予知に成功したため、死者は62人にとどまったそうです〔『百科事典マイペディア』参照〕。

以下に、添付されてきた英文と共に写真を紹介します。

Here is something not many of us get to see, unless you live near there - Mt. St. Helens at sunrise. Mt. St. Helens continues to spew ash, while it is forming a lava dome in the crater and still having minor tremors. Here in this sunrise shot, she appears to be blowing smoke rings (and anything so benign is welcomed, given recent history). What forms the "smoke rings" is the air flowing over the mountain getting pushed up higher as it goes up and over the top. The moisture content and initial temperature are just right so that the moisture condenses from a vapor to small particles at the higher altitude. When the moving air moves past the peak and comes down again, the particles evaporate back to an invisible vapor. The two "pancakes" describe that there are two layers of air for which this is happening, thus making this awesome picture possible.