I am looking for historical and current data on glaciers. Data such as glacier length changes, mass balances, imagery, flow speed, outline, runoff, etc. Does anyone know websites and databases providing these data?
The World Glacier Monitoring Service
The World Glacier Monitoring Service hosts database with mainly mass balance, front variation and thickness change data. The main website is:
http://wgms.ch/ the map with data can be found here: http://www.wgms.ch/metadatabrowser.html
The Global Land Ice Measurements from Space initiative hosts another extensive database on glaciers, this one mainly containing shapes of glaciers: the glacier outline and the basins of (parts of) the glacier. The main website can be found here: https://www.glims.org/ the map can be found here: http://www.glims.org/maps/glims and the downloadable inventory here:
World Glacier Inventory
Based on the WGMS dataset it contains data such as location, area/lenth/width, elevation, classification, orientation, and ablation and accumulation area:
U.S. Geological Service
In my experience, the U.S. Geological service is happy to provide data when asking them. This is their website:
Additional datasets: National Snow & Ice Data Center
The NSIDC has gathered links to over 200 different data sets on glaciers, amongst which the glacier databases I named in this answer. They also have links to datasets on specific regions with various quantities, such as bedrock elevation, atmospheric values over the glaciers, images, etc.: http://nsidc.org/data/search/#keywords=glaciers/sortKeys=score,,desc/facetFilters=%257B%257D/pageNumber=1/itemsPerPage=25
Furthermore, a database on U.S. glaciers is being set up here: http://glaciers.research.pdx.edu/
Several countries with glaciers prefer to keep all data on these glaciers confidential. This is especially true if the glacier's runoff feeds a river flowing into a neighbouring country. Parts of the Himalayas are a good example of this.