The KNMI has investigated the ice thickness in Central Netherlands using computer calculations. An ice layer of more than 10 centimetres occurs in some winters for dozens of days.
Record ice thickness
In the winter of 1991, the ice was thicker than ten centimetres on eighteen days.
In the very severe winter of 1963, it was even thicker on eighty days.
That winter, the ice must have been more than forty centimetres thick.
In the winter of 1996, the ice reached a thickness of 25 centimetres.
That was 3 to 4 centimetres less than in the winter of 1979 and in the winters of 1985, 1986 and 1987.
On 11 January 1997, at the end of the first frost period, the ice in De Bilt had grown to 32 centimetres.
This is the thickest layer of ice since the winter of 1963.
Skating ice
The carrying capacity of good ice is 4 to 5 centimetres for an adult man.
A large crowd of people is safe with an ice thickness of 27 centimetres.
Elfstedentocht
Most Elfstedentocht (eleven out of fifteen) were held with ice thicknesses of more than 25 centimetres.
In 1985, the tour was held on 17 centimetres of ice, in 1917 on only 15 centimetres.
The thickest Elfsteden ice was in 1940, when it was over 41 centimetres.
