While the wintry weather of the past week gives way to spring-like weather with temperatures rising to 17 degrees, today marks exactly 40 years ago (on February 21, 1985) the second-to-last real Eleven Cities Tour was held as the thaw had already begun. Due to the dwindling chances of the Tour of Tours, an Alternative Eleven Cities Tour has been held on the Austrian Weissensee for years. That always seemed a sure thing. But even there, the climate is changing rapidly, and the chances are diminishing, as this year has shown.
The thaw had already begun
First back to 1985. Since 1963, everyone had been looking forward to this day. 22 years of waiting were rewarded. The whole of the Netherlands saw Evert van Benthem win the race on February 21, 1985, and thousands then skated the tour. Among them my KNMI colleague Reindert: I doubted until the last moment. Should I go, or should I not? I hadnt been able to practice much, and the thaw had already begun. But, when will you get another chance? So I went! Southwest wind. Yes, that was nice, a tailwind from Stavoren, skating from group to group. In the evening it became tricky, with puddles on the ice. All those people... Against the wind from Dokkum, the last kilometers on your last breath, making sure you didnt fall. But... reached Leeuwarden!
The long wait began
After 1985, 1986 followed with another Tour. In 1987 almost. Then years of nothing. Only in 1997 did the mythical Tour appear again, in early January, and with beautiful ice. Incredible. It could still happen, and so early in the year. The feeling prevailed that we often had bad luck with the timing of the winter period. After the high of 1997, it became quiet again. Very quiet. Only in 2012 did the prospects seem old-fashioned favorable, but snow threw a spanner in the works. The ice didnt grow fast enough, there were still holes, and the celebration didnt go ahead. In the years that followed, skating on natural ice still took place. Sometimes for a day, sometimes for several. Also, technology is not standing still, and nowadays we can regularly skate on thin ice with the right preparations and on specially prepared ice rinks. But as delightful as skating in circles on a natural ice rink is, it is not an Eleven Cities Tour.
Dwindling chances due to warming
For every winter since 1920, we calculate the average temperature in De Bilt of the coldest 15-day period (image 1). The Eleven Cities Tour could usually be held if that temperature dropped below -4.2℃ (the years with the dots). We conveniently call this eleven cities weather. What the graph shows is that eleven cities weather is occurring less frequently due to warming. We have written about this before. But, thanks to our unpredictable winter weather, the chance is not yet completely zero.
Image 2 shows the relative difference between the longest and average length of a period below -4.2 degrees. This makes a difference of more than a factor of 10 in our country. Our country is therefore on the edge where much is to be hoped for. If it does get really cold here, there is also a real possibility that the cold will last longer. Going further north, east, or into the mountains, eleven cities weather becomes more of a certainty. Here it is possible, but it is really special. So we can still hope that a Scandinavian high-pressure area settles in a favorable location for several weeks, allowing cold to be transported to Friesland. A little snow is welcome, especially if the ice is already a bit thicker. But further, please, an easterly wind and a clear sky.