In a joint project of computer- and geo-scientists, wireless sensor networks (WSNs) are customized for permafrost monitoring in alpine areas. In this paper, we discuss requirements for a rugged setup of such a network that is adapted to operation in a difficult environment. The experiences with a first deployment at Jungfraujoch (Switzerland) show that, beside hardware modifications of existing WSN platforms, special emphasis should be given to the development of robust synchronization and low-power data routing algorithms. This results from the fact that standard software tools are not capable in dealing with the high-temperature fluctuations found in high-mountains without compromising the power consumption and the network topology. Enhancements resulted in a second deployment at Matterhorn (Switzerland), from where we expect results in the near future. Once the technology of WSNs is a science-grade instrument, it will be a powerful tool to gather spatial permafrost data in near real-time.