South Dakota’s Strangest Day Ever Happened in Spearfish in 1943
Some folks say it's why we live here in South Dakota. The change of seasons.
You see, one minute it was 4 degrees below zero. A bit on the cold side for sure, but not all that unusual. But then... 2 minutes later it was 45 degrees. That's right, in 2 minutes the temperature rose 49 degrees! Let me say that one more time... 2 minutes!
Then it bumped up to 54...before falling back to 4 below zero. And that all happened in one morning. These poor folks went from parka to sweater to t-shirt and back to parka.
The huge and fast temperature change reportedly cracked windows and instantly frosted car windows to the point drivers just pulled over and stopped.
So what in the world (or other-world?) caused this weather phenomenon?
Well, apparently an extremely cold blast from the north and east ran smack dab into an extremely warm airflow from the west, and...voila! Once the winds calmed back down the cold air mass took over again.
Oh, it caught national attention alright and in fact, even made the then hugely popular 'Ripley's Believe It Or Not'.
From the National Weather Service:
In Spearfish, the temperature rose from -4 at 7:32 a.m. to 45 degrees–a rise of 49 degrees—in just two minutes. A couple of hours later, it plunged from 54 back to -4 degrees–a change of 58 degrees in 27 minutes. In downtown Rapid City, the temperature had warmed to +5 degrees by 9:20 a.m., then it quickly warmed to 54 degrees by 9:40 am—a difference of 49 degrees in 20 minutes....The change in temperature was noticeable as people rounded street corners. Motorists were unable to see out their windshields when thick frost forms as they encountered the front and plate glass windows cracked.
WeatherNationTV.com has graphs showing the phenomena.