Stockholm traffic chaos or what happens if there is no plan B

This winter the snow clearance work has failed in Stockholm. The streets and the sidewalks have been so icy so lots of people have ended up in emergency care with fractures. Now the trains and the metro fail too which causes total chaos.

Why is it so? Stockholm has had snowy and cold weather many times (although not every winter). Normally it's only some local trains that don't run on time, because they were built in some warm country without the right winter requirements. Everybody knows that. But why did other things fail as well this year?

I believe it's because all the routines, all the requirements and plans could only handle a normal case. There are few or no routines for a slightly abnormal case. It seems nobody asked the questions "but what if it's not a normal case?"

I lady originating from southern Europe told me that the temperature is always around zero degrees when it's snowing. She had noted that during the few years she had been living in Stockholm. I didn't think it was a general rule, but I had problems to prove her to be wrong. Last year when our conversation took place her statement was true. It was only snowing when the temperature was around zero degrees. However, it has not been true this year.

Apparently the snow clearance people and the traffic planning people have only been planning for that normal mild weather case too.
The snow clearance people usually remove snow from streets and sidewalks in a rather careless way. They get away with it, because they use salt to melt away the rest of the snow. Usually the salt makes it look like an early spring with water pouring off the streets and the sidewalks a few days after a snowfall.

It seems the trains use another techniques. They add some electricity to melt away the snow from trails and switches with heat.
I usually use electricity and heat to get my car nice and warm too. By heating it up a few hours per day and by using heat on the windows when driving I usually keep my car fairly safe and comfortable even during the wintertime. Except this year. This year having the heat on made my car turn into an ice igloo.

It has been quite cold lately also when it has been snowing, it hasn't been around zero degrees, but much colder. So I've learned to avoid having the heat on the windows or use the windscreen wipers when driving in snowy weather. Since the snow is so cold and light it has been blowing away by the wind when driving.

The salt that was added to the sidewalks just made them icy, since the weather turned cold instead of warm afterwards. The electricity that has been added to the trails just made them covered with ice, instead of making them cleaned from snow.

The conclusion is that they need to have some routines for a plan B too. When the weather isn't going to be warm, salt should be avoided on the streets, and the snow have to be removed properly and not in a careless way (instead of relying on melting it away with salt).
When it's too cold, maybe electricity and heat shouldn't be used to get the snow off the trials, but maybe the snow needs to be blown away instead. It's all about having the right requirements and the right routines for the abnormal case too. To avoid the chaos we see in Stockholm today...