The Saguaro National Park in southeastern Arizona is home to unique mountain ranges known collectively as the Sky Islands. The Sky Islands are Biodiversity Hotspots and host different ecosystems, ranging from arid deserts to temperate forests. Snowmelt provides a source of water during the dry season for the various flora and fauna that inhabit the Sky Islands. However, change in snow cover is a growing concern for the National Park Service (NPS) who monitors water presence. A complete record of snow presence does not exist due to the remote and rugged topography of the region. As a result, it is difficult to study how water resources are changing in the Sky Islands and what effect this has on wildlife and vegetation. This project used NASA Earth observations to aid the NPS in understanding the role of snow cover in the Sky Islands. Historical snow cover maps were created to address the current gap in information regarding snow presence. With a more complete understanding of the impact of snow cover, the NPS will be able to analyze past snow cover changes to improve future land management decisions.