They have been observed to climb up to 2 metres (6.6 ft) on vertical walls of basement ducts, where they hibernated, on wet nights. [13]:105–107 Migration to breeding sites occurs on sufficiently warm (above 5 °C) and humid nights and may be delayed or interrupted for several weeks in unfavourable conditions. The newts can also leave the water in case of a sudden cold snap.[13]:89–90