94 MANUAL OF MARINE METEOROLOGICAL OBSERVATIONS 



5 cm. (1.97 in.). It is easily broken by wind or swell, and makes a tinkling 

 noise when passed through by a ship. 



10123. Fast-Ice. Observe whether the amount is unusually great (heavy). 

 Fast- ice is a sea- ice which remains fast, generally in the position where 

 originally formed, and which may attain a considerable thickness. It is 

 found along coasts, where it is attached to the shore, or over shoals, where it 

 may be held in position by islands, grounded icebergs or grounded polar-ice. 

 Subdivisions are Winter fast- ice and Polar fast- ice. 



10124. Drift-ice. Observe whether the amount is unusually great (heavy). 

 Drift-ice (Pack-ice) is a term used in a wide sense to include any area of 

 sea-ice, other than fast-ice, no matter what form it takes or how disposed. 



10125. Packed (compact) slush, or packed strips of hummocked-ice. 

 Note that this condition involves drift-ice (pack-ice), and more than that, 

 the condition of the ice being packed into a compact mass, under the influence 

 of wind, swell, or current. When hummocked-ice is run together in the 

 foregoing manner to form a long narrow area of pack-ice, about 1 km. 

 (0.54 nautical mile) or less in width, it is also termed a strip (stream or 

 string). 



10126. Presence of leads near the shore. A lead (lane) is a navigable 

 passage through drift-ice. It may be so named even if covered with young- ice. 



10127. Hummocked ice. Hummocked ice refers to ice piled haphazardly, 

 one piece over another. 



10128. Ice jamming. This term refers to the action of ice that is being 

 squeezed or crowded together into a compact mass. 



10129. Icebergs. An iceberg is a large mass of floating or stranded 

 ice, more than 5 m. (16.4 ft.) above sea level, which has broken away 

 either from a glacier or from a shelf- ice formation. 



10130. BEARING, DISTANCE, AND ORIENTATION. When ice is present, 

 estimate the distance to the nearest part of the ice (ice- limit) and determine 

 the bearing to 8 points of the compass. When the ice-field is so arranged 

 that a fairly definite edge is seen, determine the orientation of the nearest 

 edge, i.e., whether the edge lies in a northeast to southwest direction, etc. 



10200. CODING AND ENTRY OF ICE DATA ON FORM 615-5 



10210. GENERAL. Ice observed at sea is coded and entered on Form 

 615-5 in "Remarks." 



10220. KIND (C2). Select the code figure from Code Table 19 that most 

 nearly corresponds with the predominant kind of ice observed, and enter the 

 figure in the "Remarks" column. 



