If you blinked and missed the first snow in Seoul, Sunday, don’t fret. After all, by weathermen’s standards, it wasn’t even called that.

First, it fell early in the morning when you probably were asleep in bed. Second, it was so light that there were no traces of evidence on the ground.

Despite all this, the first snow that weathermen claimed fell in Seoul and the western part of the peninsula was a kind of perfect storm in meteorological terms.

Three factors ― temperature, clouds and winds ― fell in place, according to weathermen.

They say that, if a band of high pressure from the continent prevails as usual at this time of the year, the weather will be clear. But, if this high pressure runs into relatively warm temperature over the ocean, it becomes a whole different ballgame, so to speak.

More specifically, the weathermen say that the unlikely first snow fell because the high cold pressure passed over the West Sea at a time when the air there was laden with water vapor, causing clouds to form and it to snow.

In other words, the weathermen say that the temperature of the high pressure was minus 9 degrees Celsius at an altitude 1.5 kilometers above sea level, when the sea water in Deokjeok Island in the West Sea was 15 degrees.

Then, the clouds created by the 24 degrees in difference blew toward Seoul, riding on the easterly wind that happened to occur at that time.

The moving clouds became heavy and snow fell.

“The main reason for snow to fall in winter is because the cold high pressure passes over the highly moist air over the sea, which in turn makes for clouds,” a weatherman said. “The clouds become so heavy that they turn into snow.”

He said that this time, the amount of clouds were small so it fell lightly, explaining that this seasonal phenomenon is sometimes very unpredictable. The Korea Meteorological Administration failed to predict the first snowfall in Seoul.

The administration records the official first snow when there is 0.1 oo a centimeter of snowfall at its observatory, with visible traces left. So, officially, Seoul has yet to see its first snow.

foolsdie@koreatimes.co.kr