Winter Cold Moon
“Duluth spent about 63 hours below zero from Tuesday night to Friday afternoon, Embarrass hit 37 below zero Friday morning and wind chills across the Northland nosed 40 below zero over the past week.
And the arctic blast isn’t over yet. A wind chill advisory remains in effect until noon Saturday for all of the Northland, with wind chill values into the 30s below zero.” Duluth News Tribune, January 6, 2017
Just an example of why Minnesota came in number 1 on a recent list of worst winters. It’s why the winters here in Colorado, which came in 47th on the same list (seems off to me, but, hey), can seem almost a different season than the one 40 years in Minnesota acclimated me to.
This week has featured both snow and snow-eaters. The snow has not been much, less than an inch, plus flurries today, though last week’s snow freshened up and plumped up our snow cover. Then, we get the chinooks, the snow-eaters.
These ferocious winds can reach 90 mph and exceeded that outside Colorado Springs with 113 mph blasts whipping a fire through a suburban neighborhood. Chinooks are creatures of the mountains. This illustration explains them very well.
In the instance of Shadow Mountain we are on the eastern, lee side, of the continental divide, the right side in this illustration. When the circumstances are right, the winds begin to fall down the lee side, gathering speed and warmth as they plummet toward the plains (adiabatic heating), also losing moisture as their temperature rises. Thus, the snow-eater.
We’ve had two long instances of chinooks this week, one tentatively underway right now. The lodgepoles dip and bend. Near their tops the trees look like they’re wrestling each other. Anything not nailed down blows away. The piles of snow melt. Note that this is not the solar snow shovel, but a separate phenomenon. Just another way in which Colorado winters differ from the sort experienced in Duluth over the last few days.
