Wind chills in parts of North Dakota reached minus 70 degrees (minus 56 degrees Celsius), while the heat index in Miami was more than 160 degrees warmer at 92 (33 degrees Celsius).
The fun part of North dakota is the extremes. The record low (without wind chill) is -60 F, the record high is 122 F. That is a 182 degree spread, or 100 C spread for the rest of the world.
I often wonder how much money Northern states would save on roads if it weren't for the extreme temperature swings.
Regularly hit highs over 100 in the summer, lows below -30 in the winter. That's an awful lot of compression and expansion. Not to mention the abuse of heavy plows and their blades catching upheaved concrete.
It’s actually too cold for salt to be reliable. Water fully saturated with salt freezes at ~-21/-6(c/f), so if it’s predictably getting colder than that, it’s a bad idea to use salt.
Edit: They add beet juice when it’s really cold, but otherwise, it looks like they use salt :(
Interesting, I haven’t found anything to support that (but it’s weirdly difficult to research, so it could just be DDG not understanding what I’m looking for), do you have a source for that?
I found halite (unrefined sodium chloride) as the primary type of rock salt in the US. Wikipedia lists beer, molasses, and beet juice as possible alternatives for roads or glycol and sugar for airlines.
The EPA does list CaCl as an option, but notes that it’s both better for the environment and more expensive, so it’s reserved for vulnerable areas. I found this which doesn’t specify which they use, but gives an effective temperature range that sounds like NaCl for North Dakota.
I lived in North Dakota for almost 5 years, they dont use salt. Just a sand/dirt mix. Things get really nasty in the spring/early summer when it all starts melting.
They were trying out a weird chemical mix when we moved away, i want to say some glycol something or other? It was actually pretty slimy but way better than ice.
Many places have switched to a brine which uses a waste byproduct from cheese production. This greatly reduces how much salt is thrown onto the roads and also makes use of literal waste
When it gets that cold salt is useless, so thankfully we see much less of it throughout the winter. Sand is used instead. -20C and salt sort of stops working.
It's wonder our roads look like they were shelled once spring rolls around. Last year was particularly bad, I don't think the roads were in decent shape until the end of the summer. At least near Minneapolis.