Ice Ice Baby

We have now experienced our first Ice Storm. A very powerful early season winter storm produced significant amounts of snow and ice across much of the middle of the US on November 30th & December 1st. Over a foot of snow fell from Oklahoma to southeastern Wisconsin, including reports of ‘thundersnow’, but we were lucky & only got about 4 inches. However, we didn’t escape the ice with accumulations of sleet & freezing rain greater than 2 inches.

Ice storms can be one of the most devastating forms of winter weather & occur when freezing rain (rain that has been supercooled) freezes upon contact with cold surfaces & coats everything with a layer of ice.

Freezing rain develops when snow falls through a layer of warm air deep enough for the snow to completely melt & become rain. As the rain falls, it passes through a thin layer of cold air just above the ground surface & cools to a temperature below freezing. However, since the cold layer is so thin, the drops do not have time to freeze & so are classified as being supercooled. Their temperature is below freezing point but they don’t freeze until they strike the ground, parked cars, road signs, power lines, tree branches, etc.

Sleet had been falling since mid-morning & although there were plenty of snow-ploughs & gritters trying to keep the roads clear, the drive home was still treacherous. Luckily, most of the freezing rain & snow fell overnight, with just about everything looking ‘Christmas card picturesque’ the next morning.

The trees & power lines were continually creaking under the weight of the accumulated ice, with a lot of these having been downed due to the additional loading caused by the ice. At one time over 500,000 households & businesses were without power throughout the St. Louis Metropolitan Area & central Illinois.