• Location: Spain; 42.73°N, 0.42°W
  • Operational Management: Pyrenean Institute of Ecology-CSIC
  • Purpose/Scientific Focus: Snow hydrology, snow-ecology interactions, site for testing meteorological and snow measurement techniques and sensors.   


  • Location (Physiographic Region): Central Spanish Pyrenees, headwater of Gállego River, near the Spain–France border. 
  • Area: 0.33 km2 
  • Elevation: Min. 2,056 m to Max. 2,340 m  
  • Description (Physical–Ecological–Climatic Characteristics): Small subalpine catchment dominated by alpine meadows and small bare ground zones. Gentle slopes and lithology dominated by slates and sandstones with very reduced role of groundwater.
  • Drainage/River System: Gállego River, which is one of the main tributaries of the Ebro River.
  • Site History/Historical Context: It was created in 1986 with meteorological information of varying quality since 1996. Much better information after 2011 but reliable precipitation and runoff data is still an issue.
  • Main Land Cover(s): Subalpine meadows.
  • Lithology/Soils: Sandstones and slates.
  • Mean Annual Temperature: 3°C
  • Mean Total Annual Precipitation: 2000 mm
  • Snow Characteristics: Deep snowpack mostly in isothermal conditions. 
  • Years of Data: 12 (the most reliable) 

Stations & Observations

Observational Stations and Sites

Type Station Name Latitude Longitude Elevation Notes/Details
Meteorological Izas 42.74268°N 0.41912°W 2113 m  Temperature, relative humidity, wind speed and direction, precipitation, broadband albedometer, ultrasonic snowdepth, ground heat flux, soil temperature
Hydrometric Izas °N °W 2056 m Water level, water temperature and electric conductivity

Field Observation Campaigns and Other Measurements

Measurement Instrument Description Spatial/Temporal Resolution and Coverage Notes/Details
Terrestrial Laser Scanner Riegl LPM 321 7 per snow season 2012-2018
UAV Sensors Ebee, Inspire 300 7 per snow season 2019-2023
Time-lapse Photographs Campbel 1mpx 3 daily, 2010-2023

Data Availability

Geospatial Data

Landcover and Soils Soil and vegetation maps avaialble
Stream/River Network
Basin Delineation/Shapefile Basin shapefile is available


  • very rich catalog of snow maps from TLS and UAV

Observational Data Availability 

  • Revuelto, J., Azorin-Molina, C., Alonso-González, E., Sanmiguel-Vallelado, A., Navarro-Serrano, F., Rico, I., and López-Moreno, J. I.: Meteorological and snow distribution data in the Izas Experimental Catchment (Spanish Pyrenees) from 2011 to 2017, Earth Syst. Sci. Data, 9, 993–1005, https://doi.org/10.5194/essd-9-993-2017, 2017.   

Modelling Activities

The CRHM model has been applied several times to investigate snow processes and their sensitivity to environmental change.

  • López-Moreno, J.I., Pomeroy, J.W., Revuelto, J. and Vicente-Serrano, S.M. (2013), Response of snow processes to climate change: spatial variability in a small basin in the Spanish Pyrenees. Hydrol. Process., 27: 2637-2650. https://doi.org/10.1002/hyp.9408 

Contact & Further Information

Additional Information (Key Papers)
  • Revuelto, J., López-Moreno, J. I., Azorin-Molina, C., and Vicente-Serrano, S. M.: Topographic control of snowpack distribution in a small catchment in the central Spanish Pyrenees: intra- and inter-annual persistence, The Cryosphere, 8, 1989–2006, https://doi.org/10.5194/tc-8-1989-2014, 2014.
  • López-Moreno, J. I.Revuelto, J.Fassnacht, S. R.Azorín-Molina, C.Vicente-Serrano, S. M.Morán-Tejeda, E., and Sexstone, G. A. (2015), Snowpack variability across various spatio-temporal resolutionsHydrol. Process.2912131224, https://doi.org/10.1002/hyp.10245  
  • Revuelto, J.López-Moreno, J. I., & Alonso-González, E. (2021). Light and shadow in mapping alpine snowpack with unmanned aerial vehicles in the absence of ground control pointsWater Resources Research57, e2020WR028980. https://doi.org/10.1029/2020WR028980
  • Revuelto, J., Gómez, D., Alonso-González, E. et al. Intermediate snowpack melt-out dates guarantee the highest seasonal grasslands greening in the Pyrenees. Sci Rep 12, 18328 (2022). https://doi.org/10.1038/s41598-022-22391-x