Theoretical predictions of thermal ice loads often result in over estimations. The most important discrepancy between theory and practice is the idea of an ice sheet without cracks. Field measurements of in situ stresses have shown that the ability to build up thermal stresses may vary from 130 to 290 kPa/°C in the same effectively confined ice sheet.

Large volumes of natural ice contain thousands of fine dry cracks and also systems of wider cracks. This affects thermal ice loads in two ways:

The expansion needed to close dry cracks delays the pressure start.The lateral restraint of uncracked ice decreases because of concentrated creep processes around the cracks.A nonlinear continuum model is used to analyse the stress measurements. This model treats the ice as an uncracked continuum on average.

In this paper also a simplified stress-strain relationship for cracked ice is proposed. In this simplified model the ability to build up compressive stresses increases linearly with stress level and the creep rate is proportional to the square of the stress level.