Initial Findings

Comparing the snow extents of 2013 and 2024 showed a reduction in snow extent. In the animation below (left), it's clear that the extent of the snow is larger and more spread out in 2013 compared to 2024. To help validate this claim, the change detection map (right) shows areas that changed are largely around the edges of the snow extent. Additionally, there are several large pockets within the snow extent that did show less change. 

Comparing snow extent in NDSI images

By visually comparing the extent of snow in each of the NDSI images, it can be difficult to discern changes between the two years without an overlay or animation. However, there are some noticable patterns. For example, it's clear that the 2013 image has more frequent and larger gaps across the snow extent compared to the 2024 image. Additionally, the snow extent is slightly larger and wider in 2013, but less homogenous compared to 2024. The 2024 image has more snow coverage in the middle of the mountain range that is not covered by snow in 2013. This suggests that these areas are not glaciated, and may simply be influenced by annual snow fall. Since these are areas in the middle and highest elevation part of the mountain range, snow could occur in these areas even during thre summer. Compare this to lower elevation areas where snow is less likely to occur during the summer, and are more susceptible to warming temperatures. These lower elevation areas appear to be largely where snow extent declined. 

Differenced NDSI image Results

This image quantifies the observations made from comparison of the two NDSI images above. While some areas of the snow extent gained snow, these areas are at higher elevations, and may not necessarily be glaciated and hold a large amount of ice/snow. Since these areas were not covered in snow/ice in 2013, it's unlikely that they have become glaciated in 2024. Glaciers can take decades or hundreds of years to form according to NASA, meaning that these areas are likely just covered in a layer of snow that will not be as long lasting as glaciated areas (Lindsey, 2024). 

Additionally, areas represented in red show where snow and ice extent decreased over the study period. These areas are largely on the edge of the snow extent, meaning that they are at lower elevations which are more susceptible to warming. 

While the change detection map is useful for identifying areas where snow extent changed, this map is particularly useful for understanding and visualizing the exact nature of the changes that occurred.