Explaining why rock salt doesn't melt ice on the roads in extremely cold temperatures

SYRACUSE, N.Y. - Bitter cold air has dropped in across the United States this week due to the polar vortex. Plus, snow is on the way for CNY heading into the weekend, leading to snowy/icy road conditions. Rock salt won't work as well on the roads due to extra cold temperatures and gusty winds.

High temperatures over the past couple of days in Texas were as cold as it was in CNY. Plus, a good portion of the country has been experiencing high temperatures in the 20s to teens, even as cold as the single digits in the Midwest. The only warmer air is far southeast and southwest.

First let's explain why there is a big drop of colder air across the country. This is because of the polar vortex, which is a large area of cold air at the poles, usually contained far north due to the jet stream.

The jet stream is an area of fast flowing winds higher in the atmosphere. When the jet stream is strong, it stays straight and contains this colder air up north. However, when the jet stream is weak it wobbles and allows this colder air to drop further south across the United States. This is the scenario for this week.

The coldest air in CNY arrives on Saturday with temperatures starting the morning in the single digits, only reaching the lower to mid teens in the afternoon. However, gusty winds will make it feel like the negatives to single digits all day. Plus, widespread light snow showers develop on Friday, then lake effect snow in CNY on Saturday, which will lead to deteriorating road conditions. From snow covered to slushy roads, transitioning to icy spots.

The rock salt put down on the roads won't do it's job as well because of the cold and windy conditions this weekend. This is because rock salt doesn't really melt ice when the temperature is below 15 degrees. Rock salt is used on ice to lower the freezing point of water, usually down to about 15 degrees. But when the temperature is colder than that, it will take a higher concentration of salt to melt the ice, plus it will take a lot longer to melt. However, with gusty winds forecasted this weekend, it will likely blow most of the salt off the roads, keeping a layer of ice.

Drive especially careful this weekend in CNY as roads are likely to be icy in spots!

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