Freezing Fog In Rapid City SD

Here's what the National Weather Service had to say about us one day in December: URGENT - WEATHER MESSAGE:EASTERLY WINDS WILL CAUSE DENSE FOG TO FORM...FREEZING FOG ADVISORY IN EFFECT UNTIL 5 AM MST WEDNESDAY WHEN A STORM FRONT MOVES IN... A FREEZING FOG ADVISORY MEANS NEAR ZERO VISIBILITY IS OCCURRING *DENSE FREEZING FOG WILL PERSIST * THE FOG WILL ALSO CAUSE ICE ACCUMULATIONS ON THE GROUND... THE FOG WILL CREATE ICE ON ROADS AND SIDEWALKS...SO WATCH FOR SLIPPERY AREAS.

Well, that sounded dire! And it was if you were trying to rush through city streets to get your Christmas shopping done. An approaching storm on Wednesday translates to snow, wind and cold on top of the freezing fog, with wind chills expected to be well below zero.

So that forecast makes today the best day! And that's why drivers are out there sliding through stop signs and scraping jagged frost needles off their cars!

Freezing Fog Sets In

All the folks here who head east for Christmas are trying to leave early or travel north through North Dakota to avoid the coming storm. And there are plenty of folks out here with relatives in eastern South Dakota and Minnesota.

That's a long, hard drive in winter conditions; I speak from bitter experience since I was once trapped in a blizzard on I-90 west of Wall and once stranded in an ice storm in Sioux Falls. That's when my late husband, Mark, and I gave up traveling east in the winter!

So instead, Brian, Leesha and I drove out to take pictures of freezing fog -- Leesha was very excited about all the smells. We didn't know freezing fog had a scent, but she certainly picked up something!

Frost-Encrusted Spent Blossom

Freezing fog occurs when the water droplets that the fog is composed of are "supercooled". Supercooled water droplets remain in the liquid state until they come into contact with a surface upon which they can freeze. I've lived in Rapid city for thirty years, and these ice storms are a new phenomenon -- climate change has arrived.

As a result, any object the freezing fog comes into contact with becomes coated with ice. The same thing happens with freezing rain or drizzle. So here are more of the results: