Perennial snowfields are an important component of Arctic National Parks in Alaska, but with pronounced warming, the Arctic is shifting rapidly and these individually small, but widespread features of the cryosphere are rapidly retreating. These snowfields tend to be thinner than glaciers and are particularly sensitive to climate change. The process of perennial snowfield retreat is important to understand because snowfields are valuable ecosystems for an array of wildlife, influence local hydrology, and alter geology and permafrost. Caribou flock to snowfields in the summer to stay cool and avoid mosquitos. Rare, well-preserved archeological artifacts and paleoecological specimens have been found preserved in snowfields in other places in the Arctic, but artifacts perish quickly when thawed. Reductions in perennial snow cover might also affect lichen growth, which has implications for caribou grazing and movements.
To study extent changes in snowfields, their archaeological potential, and their relationship to wildlife, an extent model that maps and classifies individual snowfields by proximity to caribou was created. This model was derived by combining caribou movement data from the Western Arctic Caribou Herd with a Landsat satellite imagery-based snow persistence map for Northwest Alaska. Snowfields in close proximity to caribou were then prioritized for field survey based on possible ease of access by ancient hunters.
In the summer of 2015, a ground field survey and helicopter-based aerial survey were then conducted to look for artifacts and investigate locations and extents of the snowfields. Results of the fieldwork indicate good agreement between modeled and field-surveyed locations of snowfields. To date, no archaeological artifacts have been discovered, however, well-preserved animal remains were collected, as were baseline hydrological data. Work is ongoing to quantify perennial snowfield extent changes.
A proposed model of change in snowfield extent could prove helpful to archaeologists looking to target future field surveys, as well as help hydrologists, wildlife biologists, and others, understand how rapid declines in perennial snowfield coverage in the central Brooks Range may be affecting wildlife, hydrology, and ecology.