Maintenance is planned for NSIDC's network on Thursday, October 15 between 6:00 a.m. and 8:15 a.m. (U.S. Mountain Time). Brief disruptions in access to the NSIDC web site and data archive are possible during the maintenance.
old snow
deposited snow whose transformation into firn is so far advanced that the original form of the ice crystals can no longer be recognized.