By Steve Roark
Volunteer, Cumberland Gap National Historical Park
Ah Spring! After a cold winter, we get one of those sunny, balmy days where the temps get up into the 60s and everybody sheds coats and dreams of gardening or fishing. Then along comes a cold snap that feels colder than what it is because your body had immediately acclimated to that warmth and sunshine. Those cold snaps are regular events that have been around before TV meteorologists, and our forefathers had to watch nature to determine when to plant crops. So through the ages we have weather lore that is still with us today.
Of course, I’m talking about the names we have for all the cold snaps based on bloom times of plants. Redbud, dogwood, and blackberry winters are the more common ones you’ll hear, but I’ve also heard of locust winter, and my grandmother called one of them “snowball bush” winter, one of which she handily had growing in her backyard. Dogwood was one of the more important indicators to farmers back in the day to not plant tender vegetables until after they bloomed. Natives used dogwood blooms to determine when to plant corn. Blackberry winter probably got its start from the fact that old-timers thought that blackberries needed a cold snap to set buds on their canes.
So is all this old time weather lore correct according to science? Yes sir! A cold snap in the spring is referred to as a “singularity,” a weather phenomenon likely to occur with reasonable regularity around an approximate calendar date. Best I can tell, what they are saying is “you know it happens around a certain time of year, but not exactly when.” Indian summer is another weather singularity.
I sought to learn what exactly is going on atmospherically to cause these annual spring cold snaps. For dogwood winter I got “thermal currents make a short reversal in direction, bringing a few days or even a week of cold weather.” You get that?
Blackberry winter is even better: “a somewhat less severe return of a continental polar air mass after the maritime tropical air masses have begun to dominate the weather.”
I think I’ll just stick with watching the blooms and put my jacket on.