On smaller glaciers I'm using the JOSM magic wand plugin. On larger glaciers, Like Borealis, I'm using a combination of the magic wand and manual edits to update. 

I was hoping to have Skagit County done by Tuesday evening for the PSQGIS monthly meeting. https://www.meetup.com/puget-sound-qgis-users-group/events/290856393/ But there are still 70 some glaciers that need review. 

BTW - I reached out to David Shean for help mapping glaciers. Did you see him in the news recently?

Note - NAIP imagery is being used. While Bing's is newer it was taken earlier in the year which shows more snow cover.