APPENDIX C: SELECTED SEA-ICE DATA AND SEVERITY INDEX FOR
THE NORTH COAST OF ALASKA, 19531993 (FROM USN/NOAA NIC 1994)
Rank
Year
nm
nm
nm
nm
Date
Date
Days
Days
Meters
Outlook
1
1958
50
150
50
210
07/19
10/25
92
99+
285
fav
2
1968
25
165
30
200
07/19
10/18
86
91
275
fav
3
1993
0
130
5
185
07/18
11/07
64
112
358
unfav
4
1962
25
150
30
150
07/19
09/30
49+
68+
265
fav
5
1973
5
80
5
190
07/31
10/20
73
82
280
fav
6
1954
20
115
20
210
08/01
09/30
38+
61+
285
fav
7
1963
5
130
5
130
08/13
10/18
67
67
300
unfav
8
1960
0
90
40
90
07/23
10/12
75
105
289
fav
9
1961
15
105
15
135
07/25
09/24
49+
62+
255
fav
10
1979
0
125
0
125
08/04
10/08
31
56
309
unfav
11
1989
10
70
55
110
07/19
10/22
34
95
296
unfav
12
1974
10
100
10
100
08/06
10/05
35
61
255
fav
13
1978
5
70
30
95
07/25
10/09
35
76
231
fav
14
1986
10
80
10
110
07/29
10/21
30
58
298
unfav
15
1977
5
55
25
85
08/02
10/15
63
74
251
fav
16
1959
20
65
20
65
07/19
10/06
42
86
250
fav
17
1982
0
85
0
95
08/03
10/10
21
69
268
fav
18
1972
0
60
30
90
07/31
10/01
45
63
270
fav
19
1957
5
45
70
60
08/01
10/06
18
67
255
fav
20
1987
0
10
0
85
08/05
10/30
35
59
287
fav
21
1981
0
0
35
100
07/26
10/01
0
66+
221
fav
22
1985
0
35
0
55
08/01
10/15
22
52
301
unfav
23
1967
15
0
30
50
07/25
10/12
Unk
68
275
fav
24
1984
0
25
0
50
08/11
10/15
21
42
309
unfav
25
1966
5
0
5
45
08/01
10/22
24
65
375
unfav
26
1992
15
0
15
75
08/09
09/19
24
37
297
unfav
27
1965
0
10
0
70+
08/25
09/25
25
32
300
unfav
28
1980
15
25
15
25
08/05
09/30
11
42
359
unfav
29
1953
0
0
5
35
07/27
09/16
5
52+
330
unfav
30
1976
0
15
0
15
08/15
10/07
21
53
307
unfav
31
1971
0
0
0
30
08/23
11/01
8
71
295
unfav
32
1991
0
0
0
20
08/16
10/02
0
46
304
unfav
33
1960
0
0
20+
20
08/05
09/07
0
34
290
unfav
34
1988
0
0
0
25
08/09
09/20
0
32
236
fav
35
1983
0
10
0
10
08/08
09/16
0
21
277
fav
36
1964
0
0
0
5
08/13
09/20
0
39
310
unfav
37
1970
0
0
5
0
08/06
09/14
0
32
295
unfav
38
1956
0
0
0
40
09/07
09/30
0
24
300
unfav
39
1969
0
0
0
30
09/07
09/18
5
12
240
fav
40
1955
0
0
5
15
09/13
09/24
0
12
310
unfav
41
1975
5
0
5
0
Never
Never
0
0
290
unfav
NOTES:
Column 3--Distance from Point Barrow northward to ice edge (10 Aug)
Column 4--Distance from Point Barrow northward to ice edge (15 Sep)
Column 5--Distance from Point Barrow northward to boundary of five tenths ice concentration (10 Aug)
Column 6--Distance from Point Barrow northward to boundary of five tenths ice concentration (15 Sep)
Column 7--Initial date entire sea route to Prudhoe Bay less than/equal to five tenths ice concentration
Column 8--Date that combined ice concentration and thickness dictate end of prudent navigation
Column 9--Number of days entire sea route to Prudhoe Bay ice free
Column 10--Number of days entire sea route to Prudhoe Bay less than/equal to five tenths ice concentration
Column 11--Primary indicator of ice season severity...sum of values for 1000 mb heights at point A (52N/100E) and point B (70N/140E).
Column 12--Value in column 11 indicating favorable/unfavorable summer ice conditions (<290 m = favorable; >290 m = unfavorable).
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