The Cryosphere
The cryosphere describes those portions of Earth's surface where water is in solid form. This includes snow, sea ice, glaciers, permafrost, etc.
Snow
Snow is precipitation in the form of ice crystals, originating in clouds where air temperatures are below freezing (0˚C, 32˚F), and generally where ground temperatures are less than 5˚C (41˚F).
Sea Ice
Sea ice is formed at the sea surface by the freezing of seawater. In contrast to icebergs, glaciers, ice sheets, and ice shelves, sea ice forms and melts entirely in the ocean.

GCW News

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Updated timeline of satellite missions supporting observations of the cryosphere
Updated timeline of satellite missions supporting observations of the cryosphere

A graphical timeline showing satellite missions that support observations of the cryosphere (snow, sea ice, freshwater ice, glaciers, ice sheets, and permafrost) has been updated through March 2025. The graphic was originally produced many years ago by Mark Drinkwater (ESA) in part as a task of the WMO Polar Space Task Group (PSTG) and also in support of the Global Cryosphere Watch (GCW). The graphic appears on the Satellites page of this website.

28 Mar 2025
Welcome to our new colleague, Rosie Bisset!
Welcome to our new colleague, Rosie Bisset!

Welcome our new GCW colleague in the WMO Secretariat, Dr Rosie Bisset! She joined us on 1 February 2025 as a Scientific Officer in the newly established Cryospheric and Polar Infrastructure/Global Cryosphere Watch Section of the Infrastructure Department. Rosie was a postdoctoral researcher at the University of Northern British Columbia, where her main role involved working with airborne LiDAR datasets to quantify snow water equivalent in several forested watersheds within coastal British Columbia, Canada. Prior to this, she obtained her PhD at the University of Edinburgh where she focused on developing satellite and UAV remote sensing techniques for monitoring debris-covered glaciers in the Peruvian Andes and High Mountain Asia. 

05 Mar 2025
2024 snow assessment is now available
2024 snow assessment is now available

Snow Assessment for Winter 2023-2024, Northern Hemisphere and Regional Aspects.  Learn more.

05 Dec 2024
2023 snow assessment is now available
2023 snow assessment is now available

A snow assessment for 2023 is now available at https://globalcryospherewatch.org/assessments/snow/2023/. 

26 Jan 2024

The Cryosphere Now

Sea and Freshwater Ice
Snow and Solid Precip
Glaciers & Ice Caps
Ice Sheets
Permafrost
Atmosphere
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