MODIS Winter Habitat Indices (WHIs)

Composite RGB
Band 1 - Snow Cover Variability
Band 2 - Snow Season Length
Band 3 - Frozen Ground no Snow


Percent Frozen Ground without Snow Cover duration (pFWOS)
Mean: 2003-2020
Snow Cover Variability (SCV)
Mean: 2003-2020
Snow Season Length (SSL)
Mean: 2003-2020



Note the spatial coverage of the annual Winter Habitat Indices (WHIs) varies due to cloud cover, and pixels with a mean snow season length (2003-2020) of less than two weeks are masked out. Generally, combining data from multiple years (as median or mean values) results in more accurate estimates, though the annual data still retain mid to high level accuracy (see Gudex-Cross et al. 2021). For questions, please contact Volker Radeloff ( – we love to learn about applications of the WHIs and appreciate notifications when there are problems with the datasets.


The WHIs are designed for biodiversity research and other ecological applications. Three individual indices comprise the WHIs:

WHI SSL – snow season length WHI, i.e., the number of days between the first and last snow
WHI SCV – snow cover variability WHI, i.e., the frequency with which the ground switches from snow-covered to not and vice versa
WHI pFWOS – percent frozen ground without snow WHI, i.e., the frequency of frozen ground without snow days