Snow-covered surface

Snow-covered surface


THEIA group of experts in Snow-Covered Surface brings together teams from Cesbio, IGE, CNRM (CEN) and Legos. Theia Snow-Covered Surface SEC is dedicated to detect the presence of snow cover, on a continuous, large-scale basis.

The first product produced in this context is a mask indicating the presence or absence of snow and clouds at 20 m resolution from Sentinel-2 images. These data are available for download on

Theia Snow Product
Theia L2-Snow Product detects the presence of snow (in blue) and cloud (in white).

A second product provides an annual synthesis of snow cover duration per pixel between September 1 and August 31. It is also distributed on

Users are the academic sector (research laboratories in hydrology, mountain ecology), mountain water operational management agencies, industry (hydropower producers), agriculture (irrigation companies) and tourism/leisure services (ski resorts, individuals).


  • 2015: demonstrator using SPOT-4 Take 5 series on the Pyrenees and the Atlas Mountains
  • 2017: operational production of Theia Snow Product
  • 2019: Production of Annual Synthesis documenting the duration of snow cover
  • 2020-2021: development of new products


Simon Gascoin


A Resource Site :