In Calgary, the temperatures have been unseasonably warm so far for the entire month of December.  Most December days are typically below freezing, but most days in December have felt like late spring, often approaching the double digits celsius (more than 50ºF).  Nights still tend to dip slightly below freezing though.  This lead to dangerous driving conditions which, although Calgarians are used to, they cannot anticipate.  The particular threat is called black ice.  From the rare snowstorms we received in the past two months, there is a modicum of water on the roads.  Black ice forms when water freezes into a very thin layer of ice on the road.  This ice is almost impossible to see, but as does any ice, it causes a sudden loss of traction to the front wheels, causing cars to lurch or if their drivers are particularly unlucky, spin out.  Any ice can be dangerous, but drivers, and pedestrians for that matter, approach ice they can see with caution.  Drivers will go substantially slower than the speed limit, as they must to negotiate visible ice.  Thusly, the situation is more dangerous, because drivers are going the speed limit or faster.  When the temperature is -18ºC (-0.4ºF), black ice can form even in the absence of water on the ground, as the water in the air can freeze at that low of a temperature. There has been a great deal of black ice in Calgary and surrounding areas in recent weeks.  This video was taken near Lethbridge, Alberta last week.

In California, heavy storms have brought a lot of water, but it isn’t anywhere near the 11 trillion gallons (41.6 trillion litres) the state needs to emerge from drought conditions.  While their drought condition was improved from exceptional drought, in fact the worst in 1,200 years, they are still suffering from extreme drought.

Merry Christmas to all who celebrate it, and happy holidays to everyone who does not.

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