From GRL:

Even though the arctic zone of continuous permafrost has relatively cold mean annual air temperatures, we found an abrupt, large increase in the extent of permafrost degradation in northern Alaska since 1982, associated with record warm temperatures during 1989–1998. Our field studies revealed that the recent degradation has mainly occurred to massive wedges of ice that previously had been stable for 1000s of years.

Jorgenson, Shur and Pullman: Abrupt increase in permafrost degradation in Arctic Alaska, Geophysical Research Letters, Vol. 33, L02503, doi:10.1029/2005GL024960, 2006