Cold
32 degrees F - water freezes (at sea level)
20 degrees - cloud point of #2 diesel (see below)
10 degrees - road salt (sodium chloride) refreezes
10 below - blood flow to your extremities is reduced
20 below - 10w30 motor oil turns to sludge, road salt (calcium chloride) refreezes, skin freezes within 5 minutes
30 below - 5w30 motor oil turns to sludge
40 below - soap bubbles shatter like glass Christmas ornaments, mercury freezes in the thermometer, antifreeze freezes; cloud point of #1 diesel (see below)
50 below - skin freezes within a minute, metal turns brittle and snaps like wood
60 below - cold on an unprotected forehead can knock you unconscious in minutes
70 below - skin freezes in seconds, frozen breath hangs in the air
80 below - people's voices can be heard four miles away - it's called Temperature Inversion


Cold Car Batteries
If the car doesn't start in winter, the culprit could be a failed starter or a flooded engine, but most likely, it's the car battery. There are 3 reasons the battery should be the problem.
1. Power Available - In car battery terminology, it's called Cold Cranking Amps (CCA), which is the amount of electric current a 12 volt (technically 12.6) car battery can deliver for 30 seconds at zero degrees F while maintaining a minimum terminal voltage of 7.2 volts. If at 80 degrees, a car battery has 100% strength, at 32 degrees, it has 65% of its strength. At zero, it has 40% of its strength. At 32 below, it's down to a quarter of its strength.
2. Power Needed - Even though the battery has less power, it needs more power when the motor oil is cold. At zero degrees, when the battery has only 40% power, it needs 210% of what it would need at 80 degrees.  At minus 32 degrees, it would need 350% or three and a half times what it needs at 80 degrees.
3. Power Restored - Meanwhile, a cold battery is harder to recharge than a warm one. Low temperatures increase the resistance of electrolytes which both reduces the battery's cranking power and increases the time it takes for the engine (through the alternator) to recharge the battery.

It's a wonder that cars work at all.

Cracky
When the Minnesota lakes freeze, especially with a steep drop in temperatures, the ice will Boom loud enough to be heard miles away. The tone and pitch depend upon the size and shape of the lake basin and the ice thickness.

Diesel Cloud Point - Pour Point - Cold Flow Plugging Point
Petroleum-based diesel and biodiesel fuel doesn't exactly freeze, but the paraffin wax in fuel begins to crystallize, giving it a cloudy appearance, known as the cloud point. The cloud point of #2 diesel is between 20 and 40º F. The cloud point of #1 diesel is -40º F. The key to the cloud point is that the fuel filter starts to clog. Pour point is the point when any liquid doesn't pour. But trucks and school buses conk out from fuel line clogs prior to reaching the pour point. The operational threshhold for winter diesel is the Cold Flow Plugging Point (CFPP) developed by the ASTM, which measures diesel's ability to flow through a fuel filter. Based on the CFPP, the location, and the month of the year the fuel is being sold, diesel fuel is blended to withstand extreme winter temperatures. In Minnesota, the month & temperatures are October (-4º F), November (-18º F), December (-30º F), January (-34º F), February (-31º F), and March (-24º F). Anti-gel additives are available for both diesel and biodiesel fuels. Diesel fuel purchased in September or in Arizona, without additives, may not get you where you are going in January in Minnesota.

Ice Thickness --  Minimum Thickness For Going Out On The Ice
Here's a handy Ice Thickness card to determine if the ice is thick enough to walk on or drive over. And every winter these charts are spread all over Minnesota. One problem: how do you know the thickness of the ice? You would have to break the ice to measure its thickness. And then you would know the thickness at the open spot -- it's zero! So now you'll need Ice Claws to get yourself out of this ice hole.

Tree Motion
The lakes aren't the only thing cracking; some species of trees crack like a rifle shot, due to being unevenly warmed by sunlight. Maple trees and other thin barked trees are more susceptible than aspens, black spruce, and jack pines.

The snow around hardwood trees on sunny days in February can be peppered with tiny black specks that jump! These are snow fleas! It's true; I'm not making this up. They fall out of the tree and hop about. Snow fleas aren't fleas. They are springtails: ancient herbivorous bugs that eat microscopic algae, bacteria, and fungi. Snow fleas spring off from trees uncontrollably in the spring. And that's why it's called Spring.

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Twin Cities Calendar 2011  -  January  |  February  |  March

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