U.S. Department of Transportatior United States Coast Guard r &6 iiH2-> ^/or ^> AO- "s^ Report of the International Ice Patrol in the North Atlantic 1999 Season Bulletin No.85 CG-1 88-54 U.S. Department of Transportation United States Coast Guard Report of the International Ice Patrol in the North Atlantic 1999 Season Bulletin No.85 CG-1 88-54 Bulletin No. 85 REPORT OF THE INTERNATIONAL ICE PATROL IN THE NORTH ATLANTIC Season of 1 999 CG-1 88-54 Forwarded herewith is Bulletin No. 85 of the International Ice Patrol, describing the Patrol's services, ice observations and conditions during the 1999 season. 1999 proved to be an unusual year, with only 22 icebergs finding their way below the 48'^ parallel north. While not the "lightest" iceberg season on record, the low numbers do earn 1999 a tie with the 1977 season as the ninth-mildest iceberg season in Ice Patrol history. This document chronicles this unusual and fascinating season. R. L DESH Commander, U. S. Coast Guard Commander, International Ice Patrol 3- i ' B< LU Z DC < €11 z '^ &) CEI ffl) CD r^ 2 CO 31 32 33 34 Biweekly Iceberg Charts 35 Note: International Ice Patrol did not distribute iceberg charts in 1999 due to an extremely light ice season. The following iceberg charts were provided by the Canadian Ice Service and are included for reference and continuity with past reports. 36 37 38 39 40 41 42 43 44 45 46 47 48 49 o^-Ar ^ b \ ___ \ y :i g T ^\^ ■ — To 4 i^ 1^- y 7^ - lO^ f»*l > y - <■ J - ^ in y w. C : Ui y y **^i *0 <^. r.i 1 — y 4 4 =i 4 t4 3 4f r \ DC r -r •*', ^ 5 . 4 1 -J -i to ^^7 *"'^ feS ^~>5V o c If > m ■o CD O "E C c E > s e ANALYSE D'ICEBERG ANALYSIS FOR/POUR 1200 UTC 15 JUL / JUI 1999 ISSUED BY THE CANADIAN ICE SERVICE IN OTTAWA / EMISE PAR LE SERVICE CANADIEN DES GLACES A OTTAWA I , ICEBERGS PER DEGREE SQUARE LDij ICEBERGS PAR DEGRE CARRE . , . . SEA ICE LIMIT /UMITE DES GLACES KNOWN DATA LIMIT/ UMITE DES DONNES CONNUES LD ^ 1 ^ g 5 ^ 1 50 Acknowledgements Commander, Intemational Ice Patrol acknowledges the assistance and information provided by: Canadian Ice Service Canadian Coast Guard Navy / NOAA / USCG National Ice Center U. S. Naval Fleet Numerical Meteorology and Oceanography Center U. S. Naval Atlantic Meteorology and Oceanography Center U. S. Coast Guard Research and Development Center U. S. Coast Guard Atlantic Area Staff U. S. Coast Guard Atlantic Area Command Center U. S. Coast Guard Atlantic Area Master Communications Center We extend our sincere appreciation to the staffs of these organizations for their excellent support during the 1999 International Ice Patrol season: Canadian Coast Guard Radio Station St. John's, NewfoundlandA/ON Ice Operations St. John's, Newfoundland Air Traffic Control Gander, Newfoundland Canadian Forces Gander and St. John's, Newfoundland St. John's Flight Services Office U. S. Coast Guard Air Station Elizabeth City, North Carolina National Weather Service, Maryland It is important to recognize the outstanding efforts of the personnel at the International Ice Patrol: CDR S. L. Sielbeck LCDR M. R. Hicks Dr. D. L. Murphy Mr. G. F. Wright LT T. P. Wojahn LT J. E. Andrews MSTCM S. B. Bell YN1 S. J. Hoss MST1 M. J. O'Brien MST1 L L Valliere MST1 L S. Howell MST2 J. C. Luzader MST2 H. R. Harbuck MST2 T. T. Krein MST2 P. J. Jenicek MST3 M. L Seeger This report was produced using Microsoft® Word 97 and Excel 97 by International Ice Patrol staff. 51 52 Appendix A Nations Currently Supporting International Ice Patrol Belgium Greece Poland Canada Italy Spain ''ilm]> Denmark ■ ^H I H ^H Finland France 1 1 Japan Netherlands Norway Sweden United Kingdom United States of America German Panama 53 54 Appendix B Ships Reporting By Flag ANTIGUA & BARBUDA HANSEWELL CANADA GERMANY ABITBI CLAIRBORNE HONG KONG RIXTA OLDENDORFF LIBERIA NATASHA LITHUANIA |CAPE CIRCLE° MALAYSIA Ibunga orkid lima MARSHALL ISLANDS ISEA-LAND FREEDOM Ship Reports Reports Ships Reporting Bv Flag Reports NORWEGIAN INT. REGISTER NETHERLANDS ANTILLES JO SPRUCE NORWAY CGCS HENRY LARSEN 20 EMERALD STAR 3 FRANKLIN 2 IRVING ESKIMO 2 KALVIK 1 NORTHERN PRINCESS 3 SIBIL W 1 TERRY FOX 6 SIR HUMPHREY GILBERT 1 CYPRUS MAERSK TORONTO 21 PANAYIOTA 1 *BERGE NORD 25 BRUNTO 2 MACADO 1 GREEN BERGEN 6 MUNKSUND 1 PANAMA PARNASO 9 TRENCHSEHER 3 FEDERAL MCKENZIE 1 PHILIPPINES MOOR LAKER 1 RUSSIA AKADEMIK lOFFE 1 SINGAPORE AMAZON 1 SELFOSS 1 ST. VINCENT RHONE SWEDEN •DENOTES VESSEL PARTICIPATION AWARD WINNER BLUE CLIPPER 1 JOHN GORTHON 2 55 56 Appendix C An Historical Perspective to the Mild 1999 Ice Year Donald L. Murphy Introduction By any measure, the 1999 ice year was extraordinary. In an average year, nearly 500 icebergs pass south of 48°N, the traditional boundary below which icebergs are considered to be a menace to transatlantic shipping. In 1999, 22 icebergs passed south of 48°N. In a typical year. International Ice Patrol (IIP) issues routine iceberg warnings to mariners from February through July. In 1999, Ice Patrol issued no formal warnings. HP's aerial reconnaissance usually extends well into August. In 1999, routine aerial reconnaissance was suspended after the return of Ice Reconnaissance Detachment #6 on 4 June 1999. The average iceberg season length is 147 days. There was no formal season in 1999. What made the 1999 iceberg season even more remarkable was the fact that there was no lack of icebergs in the western North Atlantic. Indeed, there were several thousand icebergs along the northern Newfoundland and Labrador coasts in May and June (See the Ice and Environmental Conditions section of this report), but only a few moved toward the shipping lanes. This Appendix provides an historical context to the 1999 season. No attempt is made to answer the question "Why did so few icebergs pass south of 48°N in 1999?", though the review of the history provides several important clues. There is an extensive body of literature (Marko, et al., 1994) by investigators who have struggled to explain the variability in the number of observed icebergs over the many decades that IIP has been keeping records. 1999's Place in History The scarcity of icebergs passing south of 48°N latitude in 1999 is unusual, but not unprecedented. Ten times in Ice Patrol's history there have been fewer than 25 icebergs reported south of 48°N (Table 1). The 1999 ice season enters into a tie with the 1977 season as the ninth-mildest iceberg season in Ice Patrol's history. Rank Year Iceberas 1 1966 0 2 (Tie) 1940 1 2 (Tie) 1958 1 4 1941 3 5 1951 8 6 1924 11 7 1931 14 8 1952 15 9 1977 22 10 1980 24 Table 1. Years with the lowest number of icebergs estimated to have drifted south of 48'N. Note: Table 1 reflects the current definition of the ice year, which runs from October through September. At various times in Ice Patrol's history it has been defined differently, for example, in 1940 and 1941, the ice year was the calendar year. In both years, it was reported in MP's annual reports that two icebergs passed south of 48°N. One of these icebergs 57 passed south of 48'N in November 1940 and was originally counted as a 1940 observation. Here it is counted as a 1941 observation. This explains the minor differences between Table 1 and the original data in IIP annual reports. Previous Mild Ice Seasons This review was conducted using MP's annual reports, which contain extensive narratives of ice and oceanographic conditions and tabulated and plotted data for each ice season. The environmental data came from a variety of sources, including oceanographic and meteorological data from IIP patrol and research vessels and volunteer reporting ships, which were asked to provide sea temperature and ice data every four hours. The sea surface temperature (SST) data were particularly useful. From these reports, IIP compiled twice-a-month SST charts, sometimes with 1000 or more reports, sometimes fewer than 100. Prior to World War II, ice observation information was gleaned from conversations with mariners operating near Newfoundland and Labrador, especially those on sealing vessels. In fact, one of the first orders of business for an IIP vessel upon its arrival in St. John's, Newfoundland, was to visit the various vessels in port and discuss their observations. IIP also made use of an extensive network of shore observers, including Newfoundland Rangers, and coastal natives. After World War II, ice patrol used aerial reconnaissance to define the distribution of sea Ice. 1924: The 1924 iceberg season was quite a surprise to IIP. Since the inauguration of the north Atlantic ice patrol shortly after the 1912 sinking of the RMS TITANIC, IIP became accustomed to active iceberg seasons. With the exception of the early World War I years of 1916 and 1917, when there were fewer reporting ships than normal. Ice Patrol had tracked several hundred to a thousand icebergs each year. In 1924, however, there was no meaningful iceberg threat to the transatlantic steamers; eleven icebergs passed south of 48°N. In April, one of the eleven reached 41°11'N latitude, but the remaining ten did not reach very far below 48°N. The mild 1923-1924 winter led to late March sea surface temperatures over the Grand Banks that were about 3°C warmer than normal. With the exception of a few patches, there was no sea ice south of Newfoundland during the entire iceberg season. Observers on the northern Newfoundland and southern Labrador coasts reported field ice arrived a month later than normal and departed early, with a maximum extent that was far less than normal. The winds at Battle Harbor, Labrador prevailed from the east, and periods of northwesterly winds were of shorter duration than normal. There was remarkably little fog on the Grand Banks, and the patrol vessels reported good weather during the April and May cruises, a peculiar occurrence. In the latter part of May, Ice Patrol found large numbers of icebergs in the bight of Newfoundland, between Cape Bauld and Funk Island (Figure 1). 58 lorai—M. (rwc^T^.Y Figure 1. Distribution of icebergs in late May 1924. 1931: In 1931, 13 icebergs drifted south of 48°N, with the southernmost glacial ice seen on 3 May at 46°32'N near Cape Race. In fact, "...not a single iceberg menaced the United States-Europe steamship tracks throughout the season." As a result, continuous ice patrols were not put into effect, in February and early March, observers reported persistent, strong northeast winds blowing for 40 days. By the end of March, no pack ice or icebergs were seen drifting by St. John's. Observations made by the General Greene, MP's oceanographic research vessel, in April and May 1931 indicated that in April the Grand Banks SSTs were generally warmer than normal. The May values were near normal. By 10 April, the sea ice extended southward to the area of 60 miles east of Cape Bonavista, the southernmost extent of the season. Although no formal patrols were instituted, the General Greene monitored ice and oceanographic conditions near the Grand Banks throughout the spring and into the summer. The seven icebergs they saw east of Cape Bonavista during their early April cruise showed evidence of rapid deterioration. General Greene also conducted a research cruise to document ice and oceanographic conditions along the Labrador (4-24 July) and south Greenland coasts. In early July, they found numerous icebergs near the Strait of Belle Isle and modest numbers of icebergs within 65 miles of the 59 Labrador coast. While conducting eight cross-shelf oceanographic transects along the Labrador coast to the northern tip of Labrador, they found no sea ice along the Labrador coast. Their iceberg survey was somewhat hampered by poor visibility, so they believed that they did not conduct a very good iceberg census. From their discussions with natives and mariners, the ice season along the Labrador coast was light and there were prevailing onshore winds. 1 940 and 1 941 : The early World War II years of 1940 and 1941 were each very light iceberg seasons, in both cases two icebergs were estimated to have passed south of 48°N (in the original IIP annual reports). In 1940, the southernmost glacial ice was seen at 47°42'N at the end of May. During these years, the usually extensive reporting network of transatlantic ships was largely absent. War disrupted customary transatlantic commerce, and most vessels, out of fear for their safety, did not provide radio reports of their position, course, speed, ice and environmental conditions. In neither year was it necessary to inaugurate a continuous surface vessel patrol. However, in both years, the General Greene carried out oceanographic measurements. Due to the lack of the normal surface patrol, they focused their attention on southern areas of the Grand Banks and the offshore branch of the Labrador Current. In 1940, General Greene found the Labrador Current had decidedly warmer minimum SSTs than normal, and surface waters on the Grand Banks were warmer than normal. In early July, a vessel reported many icebergs and growlers near the Strait of Belle Isle. Ice Patrol's annual report in 1941 suggests that Grand Banks sea temperatures were warmer than normal; however, there were insufficient SST data to draw charts. [Considering the risky operating environment, General Greene's presence on the Grand Banks in 1941 is a testament to the value IIP placed on oceanographic measurements. In fact, the General Greene served another role in May of that year when she picked up two lifeboats and 29 men from the Marconi, a steamer that had been torpedoed.] 1951: By the beginning of the 1951 iceberg season, the reporting network of volunteer ships had long since been re-established and Ice Patrol had been using aerial reconnaissance for several years. It was an extraordinary year, even among the ten extraordinarily light years of this review. Records from Argentia, Newfoundland and Goose Bay, Labrador show that the winter of 1950-1951 was one of the mildest on record with respect to snow and temperature. In February, aerial reconnaissance located few icebergs in the pack ice. In March, a series of easterly gales substantially reduced the areal extent of sea ice, which prior to that had been slightly less extensive than normal. The surface patrol vessels were placed on extended stand-by. Due in part to continued easterly winds, the April sea ice extent was well less than normal. An early April reconnaissance flight showed very meager (six small icebergs and several growlers) iceberg populations up to 56°N. Further reconnaissance in the Strait of Belle Isle showed only five icebergs and growlers. In all, six 60 icebergs were estimated to have passed south of 48°N, and none crossed south of 46°N. Aerial reconnaissance confirmed that "...at no time during the season did there exist even a remote threat to the established steamer tracks." In May, aerial reconnaissance along the Labrador coast located fewer than 100 icebergs, most near shore. This is what makes the 1951 iceberg season so unusual. In both 1924 and 1931 there were indications of substantial iceberg populations in the bight of Newfoundland, the Strait of Belle Isle, and along the Labrador coast. The iceberg population in those areas was exceedingly sparse in 1951. 1952: For the second year in a row, surface patrol vessels were not used. The February and March sea ice extent was less than normal, and in early March, persistent easterly winds were reported. At the end of March, numerous icebergs were seen in the bight of Newfoundland. In April, many icebergs and growlers were reported in sea ice along the Labrador coast to Hamilton Inlet. Despite the presence of many icebergs north of Newfoundland and along the Labrador coast, only 12 passed south of 48°N in April, none of which moved south of 47°N. During the entire season, 14 icebergs passed south of 48°N. By May, there were no icebergs on the northern part of the Grand Banks, and only scattered icebergs in the bight of Newfoundland. During March and April, numerous icebergs were seen in the vicinity of ocean station B at 56°30'N, 51°00'W by the Coast Guard cutters occupying the station. This was a very rare event. IIP speculated that these icebergs came from east of Cape Farewell rather than the Labrador side of the Labrador Sea, but, of course, the actual source is unknown. 1958: One iceberg passed south of 48°N in 1958. The year started with three months of persistent onshore winds along the Labrador coast and a mild Newfoundland winter. As a result, the extent of the sea ice near Newfoundland and Labrador was considerably less than normal and April SSTs were about 2°C warmer than normal on the Grand Banks. The surface patrol vessels were placed on standby. The southernmost extent of sea ice occurred on 29 April when a belt of broken block ice was sighted off Baccalieu Island. At the end of May, ships using the Strait of Belle Isle reported many large icebergs between 50°W and 52° W on their tracks (about 52°N). Many icebergs were reported throughout the month of June north of 50°N, and eastward for 200 miles. Between 10-21 February an ocean station Bravo vessel sighted and tracked three icebergs near 56°30'N, 51°00'W. 1966: This year is known as the year with no icebergs, with the southern most iceberg reported at 49°05'N. The December and January storm tracks were well south of normal, resulting in strong onshore winds and warmer than normal air temperatures in Newfoundland and southern Labrador. A major storm on 29 January brought hurricane force winds to the region causing much ice destruction. The maximum southward extent of the sea ice for the entire year was a narrow tongue to 47°30'N that occurred on 17 March. By April, there were only 61 narrow sea ice bands between Newfoundland and Hamilton Inlet. Higher than average SSTs were observed all over the IIP oceanic areas of interest during the season. Onshore winds persisted through March and April, which resulted in above-normal air temperatures in Newfoundland and Labrador coastal areas. Two iceberg surveys conducted along the Labrador coast, one on 14 April and the other on 7 June, located 432 and 297 icebergs, respectively. The IIP oceanographic research vessel Evergreen completed the first of two hydrographic surveys on 8 April and found "...utter absence of any defined Labrador Current." 1977: Warmer than normal air temperatures and onshore winds along the Labrador coast in fall and early winter inhibited early sea ice development. Despite the slow start, at the end of January, the sea ice edge reached Cape Bonavista, which is approximately a normal southward extent. The eastward extent was less than normal for this time of year. A limited pre-season flight in January found 34 icebergs between 55°N and 60°N, while another from the end of February to early March found 145 medium and large icebergs south of 63°N, about half the size of the normal iceberg population for that time of year. From these observations, it was evident that the 1977 iceberg season was going to be light. A series of March storms broke up and spread out the sea ice, and at month's end a rapid retreat began, aided by above-average air temperatures and predominantly onshore winds along the Labrador coast. By late May, the sea ice edge had retreated to the vicinity of the Strait of Belle Isle, leaving a small iceberg population between 50°N and 52°N. In 1977, 22 icebergs passed south of 48°N, all before the end of April. 1980: The early winter of 1979/1980 was characterized by a series of intense storms, one of which brought record precipitation and hurricane force winds to the region. Prevailing northwest winds dominated Labrador. The early development of sea ice was slightly ahead of the norm, but by the end of January, sea ice conditions returned to normal. This year was unique in that the southernmost and easternmost iceberg for the entire season were seen very early in the year. In January, the southernmost iceberg was seen at 47°40'N, 47°40'W and the easternmost iceberg was seen at 48°10'N, 45°30'W. The sea ice began its retreat in early March, about a month earlier than usual, due in large part to the passage of two very strong storms that passed through the region. In 1980, 24 icebergs passed south of 48°N. Only 45 ice reports were received from ships during the entire season. Common Characteristics of Mild Iceberg Years Four factors characterize many of the mild iceberg years: • mild winters in Newfoundland and Labrador • persistent onshore winds in the winter • warmer than normal sea surface temperatures • sea ice arrives late, departs early and is not very extensive 62 These characteristics are usually associated with the negative phase of the North Atlantic Oscillation (NAO), which describes the dominant variability in the atmospheric circulation in the North Atlantic. (See, for example, Hurrell, 1995). A negative NAO phase is associated with a weakening of the Icelandic Low and the southward displacement of its mean position. In this state, the winter storms track south of Newfoundland, resulting in east and northeast winds and relatively warm, moist maritime air over Labrador and Newfoundland. Seven of the eleven mildest years in Ice Patrol's history had strongly negative (< -1.0) NAO index values (Table 2). Three years (1931, 1952, and 1980) were neutral NAO years, with the index between -1 .0 and +1 .0. Many of the common factors of a mild season were present in 1999. For example, in March, air temperatures in Labrador and east Newfoundland were 4°C to 6°C warmer than normal, and the thickness and area! extent of sea ice were much less than normal. However, among the 11 mildest iceberg years in MP's history, 1999 stands alone in one regard. Remarkably, the winter NAO index for 1999 was 1.70, indicating a positive NAO phase. In the historical record, there appear to be two kinds of mild years: those in which very few icebergs are found near Newfoundland (1951 and 1966) and those with significant populations in the bight of Newfoundland and the Strait of Belle Isle (1924, 1931, 1952, and 1958). This suggests two fundamentally different processes, one related to the supply of icebergs to the Newfoundland area, and the other related to the movement once they are in the vicinity of the Strait of Belle Isle. One thing is certain: an iceberg year like 1999 leads to a greater respect for the variability of the iceberg threat to transatlantic shipping and the complexity of causal factors. RANK YEAR ^^Q^y^* ICEBERGS 1 1966 -1.69 0 2 (Tie) 1940 -2.86 1 2 (Tie) 1958 -1.02 1 4 1941 -2.31 3 5 1951 -1.26 8 6 1924 -1.13 11 7 1931 -0.16 14 8 1952 0.83 15 9(Tie) 1977 -2.14 22 9(Tie) 1999 1.70 22 11 1980 0.56 24 Table 2. Years with the lowest number of icebergs estimated to have drifted south of 48'N and winter (Dec-Mar) NAO index. Note: The NAO Index used here is based on the difference of the normalized sea level pressures between Lisbon, Portugal and Stykkisholmur/Reykjavik, Iceland^ (Source: University Corporation for Atmospheric Research Climate and Global Dynamics Division) 63 References Climate and Global Dynamics Division, University Corporation for Atmospheric Research. North Atlantic Oscillation (NAO) Index - Winter. URL: http://www.cgd.ucar.edu/cas/climind/nao_winter.html/ (May 2001) Hurrell, J.W., 1995. Decadal trends in the North Atlantic Oscillation and relation to regional temperature and precipitation. Science, 269, 675-679. Marko, J. R., D. B. Fissel, P. Wadhams, P. M. Kelly and R. D. Brown, 1994. Iceberg Severity off Eastern North America: Its Relationship to Sea Ice Variability and Climate Change. J. Climate, 7, 1335-1351. 64