ARCTIC SEA ICE 



117 



Arrangement 



State 



compact Continuous, although broken, 



ice with no signs of water. 



close Ice with spaces of water, but 



so close as to hinder naviga- 

 tion. 



open Ice with spaces of water suf- 



ficient for navigation. 



drift ice An area of small and medium- 



sized glagons in which water 

 preponderates over ice. 



brash ice An area of small glagons con- 



stituting the wreckage of all 

 types of ice. 



unbroken Either fast-ice or large ice fields. 



Terms for Some Characteristic Phenomena of Sea Ice 

 Not Part of the Genetic Classification 



Crack}'^ Any fracture or rift in sea ice (not navigable). 



Lead, or lane. A channel of open water in the pack ice or Arctic 



Pack; it may be navigable in the former (mostly the antithesis 



of pressure ridges). 

 Polynya}^ Any enclosed water area (other than a crack or a lead) 



among fields, floes, and glajons of pack ice or Arctic Pack. 

 Pool. A depression (or hollow) containing fresh water in the 



fields, floes, or glagons of sea ice. 

 Hole. Opening through the ice (as for instance the holes in the 



rotten ice, honeycombed in the course of melting). 

 Frost smoke. The foglike clouds of evaporation over newly formed 



water areas in sea ice. 

 Ice blink. The whitish glare on the clouds produced by the re- 

 flection of large areas of sea ice (the antithesis of water sky). 

 Water sky. Dark streaks on the clouds due to the reflection of 



polynyas or the open sea in the neighborhood of large areas of 



sea ice. 



The Polynya as a Major Regional Feature 



The definitions in this list relate to certain features considered as 

 general phenomena. A group of these phenomena, however, namely 



i-i There are three categories of cracks: (i) tidal, (2) temperature, and (3) shock and pressure 

 cracks. The two cracks of the first category are called "active tidal cracks"; one (inshore) marks the 

 ice foot, and the other (offshore) is the line of demarcation between the coastward part of the fast- 

 ice that touches the bottom in low water and that which is constantly in a floating state (see the 

 diagram. Fig. 8). 



15 For a detailed explanation see the next section. 



