> this could mean making sure the ice is 15cms thick along the entire track, and only starting it if you are 100% sure that this is guaranteed. I'm unable to f

> this could mean making sure the ice is 15cms thick along the entire track, and only starting it if you are 100% sure that this is guaranteed. I'm unable to find any official decision-making rules, let alone historical ones, but as stated elsewhere it's doubtful that the regulations have got more strict. The event has happened only 6 times in the last 70 years, in any case. Where it is useful, there is work to control water flow via locks, ice transplantation into weak points, and legal prevention of canal navigation. So, there is also more knowledge and ability to mitigate for safety concerns.