When rain falls on an existing cover of snow, followed by cold temperatures, or falls as freezing rain, it can leave a hard crust. Surface melt followed by cold can do the same. There is growing evidence that such events are becoming more common in the rapidly warming Arctic, and it is increasingly recognized that they can have pronounced impacts on Arctic wildlife, domesticated reindeer, and human activities, like travel.

Rain on snow event
Photo showing ice crust layers after a massive dual-rain-on-snow event during November 2007 on the Yamal Penisula, Siberia, Russia. Image Credit: Florian Stammler.

These events have sometimes resulted in large die-offs of reindeer because the icy crust makes it difficult for reindeer to find forage and their movements may be inhibited. The Arctic Rain on Snow Study (AROSS), a collaboration between the University of Colorado Boulder, the Alaska Pacific University, the University of Lapland and involving extensive community engagement and co-production of knowledge, seeks to better understand the distribution, severity, and changes in the frequency of rain on snow events and melt-refreeze events in the Arctic and their impacts, with a focus on hunting and in particular, reindeer herding livelihoods.  

The Arctic Rain on Snow Study project is generously funded by the National Science Foundation cross-directorate Big Ideas initiative as part of the Navigating the New Arctic funding, award number 1928230.

National Science Foundation NSIDC CIRES CU Boulder Arctic Centre University of Lapland Alaska Pacific University LEO Network