This is massive movement of Arctic air over the lower latitudes. This air is very, very cold. The majority of the country and Canada are below 32 degrees Fahrenheit.
HOW LONG DOES IT TAKE TO MOVE TEMPERATURES ABOVE ZERO GIVEN THE STARTING TEMPERATURE IS FROM -22 TO 31 DEGREES?
People have to come to understand this is a very dangerous storm.
What occurs when there is some kind of melting ingredient is a chemical interaction. In any chemical reaction there is a saturation point whereby one element in the reaction is USED UP while the other element of the reaction continues to exist or pour into the reaction, such as ice on roads.
I think there are a couple of observations I can make that might help. If there is more water than melting ingredient the freezing will occur because the melting ingredient is no longer on the roads.
There is something else, too.
It is a phenomena that occurs with salt (NaCl) and water (H20). Salt when reacting with water actually lowers the freezing point of water and increases the amount of heat it takes to melt the ice. So while there is plenty of melting ingredient on the roads, when it comes to salt there will be a resistance in the melting point on the road surface.
The reaction between Na Cl (salt) and H2O (water) uses heat to facilitate the reaction between the salt ions and the water ions. In other words, there is less melting because the reaction takes some of the heat.
...Enthalpy and Energy
If you add up the total amount of energy (click here) required to pull the sodium and chloride ions apart then subtract the energy released when they form new bonds with water molecules, you get the total amount of energy released or absorbed by the dissolving salt; in other words, the change in enthalpy. It turns out that at room temperature and atmospheric pressure this quantity is positive, meaning that more energy is absorbed than is released. For each 58.44 grams (2.06 ounces) of salt that dissolves, 0.717 kilocalories (3 kilojoules) of heat is absorbed, meaning that dissolving salt causes the solution to become colder. The change is so slight you are unlikely to notice it in everyday life....
In order for melting to occur, the reaction has to go forward between the two ionic solutions. That melting COSTS energy. So, while the salt and water do melt, the melting is resistance because the reaction requires heat to go forward. Therefore the heat requirement is higher than let's say sunlight.
I think it is the amount of the melting agent that is the culprit this time. There is no way of knowing the entire amount of ice that will fall out of the sky. So, to realize this is a very dangerous storm with uncertain roadway outcomes, it is best to stay home. It would be a far better decision if employers are making it. People will risk their lives, even if they fully understand the danger, to maintain their employment. Employers need to make that call, no different than school systems have snow days in their learning calendar.
There is no doubt people faced great danger with this storm. Stay home and stay warm.
I have stated this before, road graders work really well when the ice is too cold to remove with spreaders.
December 17, 2016
HOW LONG DOES IT TAKE TO MOVE TEMPERATURES ABOVE ZERO GIVEN THE STARTING TEMPERATURE IS FROM -22 TO 31 DEGREES?
People have to come to understand this is a very dangerous storm.
What occurs when there is some kind of melting ingredient is a chemical interaction. In any chemical reaction there is a saturation point whereby one element in the reaction is USED UP while the other element of the reaction continues to exist or pour into the reaction, such as ice on roads.
I think there are a couple of observations I can make that might help. If there is more water than melting ingredient the freezing will occur because the melting ingredient is no longer on the roads.
There is something else, too.
It is a phenomena that occurs with salt (NaCl) and water (H20). Salt when reacting with water actually lowers the freezing point of water and increases the amount of heat it takes to melt the ice. So while there is plenty of melting ingredient on the roads, when it comes to salt there will be a resistance in the melting point on the road surface.
The reaction between Na Cl (salt) and H2O (water) uses heat to facilitate the reaction between the salt ions and the water ions. In other words, there is less melting because the reaction takes some of the heat.
...Enthalpy and Energy
If you add up the total amount of energy (click here) required to pull the sodium and chloride ions apart then subtract the energy released when they form new bonds with water molecules, you get the total amount of energy released or absorbed by the dissolving salt; in other words, the change in enthalpy. It turns out that at room temperature and atmospheric pressure this quantity is positive, meaning that more energy is absorbed than is released. For each 58.44 grams (2.06 ounces) of salt that dissolves, 0.717 kilocalories (3 kilojoules) of heat is absorbed, meaning that dissolving salt causes the solution to become colder. The change is so slight you are unlikely to notice it in everyday life....
In order for melting to occur, the reaction has to go forward between the two ionic solutions. That melting COSTS energy. So, while the salt and water do melt, the melting is resistance because the reaction requires heat to go forward. Therefore the heat requirement is higher than let's say sunlight.
I think it is the amount of the melting agent that is the culprit this time. There is no way of knowing the entire amount of ice that will fall out of the sky. So, to realize this is a very dangerous storm with uncertain roadway outcomes, it is best to stay home. It would be a far better decision if employers are making it. People will risk their lives, even if they fully understand the danger, to maintain their employment. Employers need to make that call, no different than school systems have snow days in their learning calendar.
There is no doubt people faced great danger with this storm. Stay home and stay warm.
I have stated this before, road graders work really well when the ice is too cold to remove with spreaders.
December 17, 2016
By Michael S. Rosenwald and Rachel Weiner
Though Maryland and Virginia transportation crews pre-treated highways and major roadways to thwart icing, officials said a steady stream of freezing rain fell longer than expected, outlasting the salt and other treatments applied to roads before and during the storm.
Stretches of the Beltway and Interstate 95 were closed for hours.
“After a while the salt becomes diluted,” said Charlie Gischlar, spokesman for the Maryland Department of Transportation. “People travel too fast for the conditions, and once you lose control, that’s it.”...
