Sea Ledger, April 2011

2011-04-01 to 2011-04-30 · archive

issued: 452
warning-days in force: 7,302
in force at month end: 237
sea × type cells: 190

baseline: same month, previous 5 years (2010-04, 2009-04, 2008-04, 2007-04, 2006-04)

By type

type	issued	warning-days	in force at end
Exercises	87	799.7	28
Incidents	79	953.8	29
Cable ops	52	819	34
Quakes	49	207.3	6
Nav aids	43	1,184.9	31
Missiles	36	269.9	7
Derelicts	33	90.9	2
Piracy	27	232.3	6
Surveys	18	1,678.5	58
Other	8	321.9	10
Ordnance	7	139.4	7
Debris	4	12	0
Icebergs	3	11.2	0
Containers	3	10.9	1
Wrecks	2	436.4	13
Mines	1	1.5	1
Restricted	0	30	1
Spills	0	12	0
Structures	0	60	2
Volcanic	0	30	1

By sea and type · 190 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Quakes · North Pacific Oceansurge	23	129.8	4	43	5.5× / 4.2
Cable ops · South Atlantic Oceanlong running	19	134.9	5	903	0.7× / 25.8
Incidents · North Pacific Ocean	19	128.4	4	70	1.6× / 11.6
Exercises · South Atlantic Oceansurge	16	74.9	3	34	2.7× / 6
Exercises · North Pacific Ocean	13	66.9	1	34	1.0× / 12.6
Missiles · North Pacific Oceansurge	12	75.1	3	60	2.1× / 5.8
Incidents · South Atlantic Oceansurge	11	80	3	37	2.4× / 4.6
Incidents · South China Seasurge	10	138.9	2	65	7.1× / 1.4
Piracy · Arabian Seasurge	9	89.8	1	38	3.0× / 3
Quakes · South Pacific Ocean	9	29	0	—	0.8× / 11.2
Derelicts · North Pacific Oceansurge	9	19.6	0	—	5.0× / 1.8
Exercises · Japan Sea	8	74.2	2	38	1.5× / 5.2
Exercises · Bay of Bengal	8	57.4	2	29	1.8× / 4.4
Piracy · Indian Oceansurge	8	35.3	2	40	2.4× / 3.4
Nav aids · North Pacific Oceansurge	7	96.5	3	124	3.9× / 1.8
Exercises · Arabian Seasurge	7	84.1	4	62	2.5× / 2.8
Exercises · North Atlantic Ocean	7	21.6	2	30	1.5× / 4.8
Incidents · North Atlantic Ocean	6	177.8	5	75	1.4× / 4.4
Nav aids · North Sea	6	151.8	2	92	1.4× / 4.2
Surveys · South Atlantic Oceansurge	6	56.9	3	58	6.0× / 1
Incidents · South Pacific Ocean	6	24.3	3	65	1.0× / 6
Exercises · South Pacific Oceansurge	6	15.5	3	17	2.1× / 2.8
Nav aids · Gulf of Alaskasurge	6	6.7	0	—	4.3× / 1.4
Nav aids · South Atlantic Oceanlong running	5	238.7	7	983	1.3× / 3.8
Cable ops · Bay of Bengal	5	100.1	5	74	1.5× / 3.4
Cable ops · Persian Gulfsurge	5	84.9	3	108	6.3× / 0.8
Piracy · Gulf of Adensurge	5	46.5	1	39	8.3× / 0.6
Nav aids · Inner Seas off the West Coast of Scotland	5	35.9	0	—	1.8× / 2.8
Exercises · Laccadive Sea	5	34	2	30	1.0× / 5.2
Incidents · Indian Ocean	5	30.3	1	62	1.9× / 2.6
Cable ops · North Atlantic Ocean	5	30	1	29	1.3× / 3.8
Missiles · Arctic Oceannew	5	29.5	0	—	new / 0
Derelicts · Indian Oceansurge	5	15	0	—	8.3× / 0.6
Missiles · South Pacific Oceansurge	5	14.1	1	20	25× / 0.2
Derelicts · Arafura Seasurge	5	6.1	0	—	6.3× / 0.8
Exercises · Yellow Sea	4	47.6	1	38	0.9× / 4.6
Missiles · Barentsz Seanew	4	26.4	1	26	new / 0
Derelicts · Mediterranean Sea - Eastern Basinsurge	4	19.2	0	—	20× / 0.2
Piracy · South China Sea	3	54.9	2	41	1.7× / 1.8
Missiles · Japan Seasurge	3	18.9	0	—	15× / 0.2
Cable ops · North Sea	3	18.9	2	23	1.9× / 1.6
Icebergs · South Pacific Oceansurge	3	11.2	0	—	5.0× / 0.6
Containers · North Pacific Oceansurge	3	10.9	1	31	5.0× / 0.6
Ordnance · North Pacific Oceansurge	3	9.1	1	3	7.5× / 0.4
Quakes · Indian Ocean	3	9	0	—	0.8× / 3.8
Quakes · Solomon Sea	3	8.7	1	28	0.4× / 7.6
Derelicts · South Pacific Oceansurge	3	7.5	1	25	3.8× / 0.8
Exercises · Indian Oceansurge	3	7.3	0	—	7.5× / 0.4
Cable ops · Celtic Sea	3	7	1	12	1.7× / 1.8
Incidents · Coral Sea	3	2.3	0	—	0.8× / 3.6
Incidents · Mediterranean Sea - Eastern Basin	2	113.7	2	50	3.3× / 0.6
Cable ops · South China Sea	2	97.6	3	38	1.3× / 1.6
Nav aids · Celtic Sea	2	76.5	3	52	1.0× / 2
Other · North Pacific Ocean	2	61.1	2	44	1.7× / 1.2
Nav aids · English Channel	2	60.7	2	81	0.8× / 2.6
Incidents · Caribbean Sea	2	59.1	3	36	2.5× / 0.8
Cable ops · Gulf of Mexico	2	52.2	2	168	1.4× / 1.4
Exercises · Philippine Sea	2	44.2	1	34	0.7× / 3
Surveys · Mediterranean Sea - Eastern Basin	2	37	1	36	1.0× / 2
Incidents · Eastern China Sea	2	31.4	1	27	10× / 0.2
Incidents · Bay of Bengal	2	23.1	0	—	2.5× / 0.8
Exercises · Baltic Sea	2	22.2	0	—	1.0× / 2
Cable ops · Mediterranean Sea - Western Basin	2	21.4	1	21	3.3× / 0.6
Missiles · South Atlantic Ocean	2	11	1	10	5.0× / 0.4
Missiles · Arabian Seanew	2	10.4	0	—	new / 0
Surveys · South China Seanew	2	9.6	1	9	new / 0
Nav aids · Bay of Bengal	2	9.4	1	29	3.3× / 0.6
Derelicts · North Atlantic Ocean	2	8.7	0	—	2.5× / 0.8
Incidents · Japan Sea	2	6.3	2	5	5.0× / 0.4
Quakes · South Atlantic Ocean	2	6	0	—	1.1× / 1.8
Piracy · Red Seanew	2	5.8	0	—	new / 0
Exercises · Andaman or Burma Sea	2	5.5	1	8	2.5× / 0.8
Ordnance · Mediterranean Sea - Eastern Basin	1	63.4	3	39	new / 0
Nav aids · Arabian Sealong running	1	63.3	3	500	1.7× / 0.6
Other · South China Sealong running	1	60.8	2	1,018	2.5× / 0.4
Exercises · South China Sea	1	60.5	1	34	0.6× / 1.8
Nav aids · North Atlantic Oceanlong running	1	60.2	2	381	0.4× / 2.6
Surveys · Indian Ocean	1	57.6	2	89	0.8× / 1.2
Nav aids · Gulf of Mexico	1	50.5	1	51	0.3× / 3
Cable ops · Arabian Sea	1	47.5	2	76	0.4× / 2.8
Missiles · North Atlantic Ocean	1	44.5	0	—	1.0× / 1
Ordnance · Ionian Sea	1	31.8	2	32	5.0× / 0.2
Surveys · North Sea	1	30.7	1	39	1.7× / 0.6
Other · North Sea	1	30.6	1	54	0.7× / 1.4
Nav aids · Tasman Sea	1	30.6	1	66	1.7× / 0.6
Wrecks · Laccadive Sea	1	29.7	1	29	5.0× / 0.2
Cable ops · Laccadive Sea	1	27.5	1	44	1.3× / 0.8
Surveys · Gulf of Mexico	1	26.5	1	41	5.0× / 0.2
Incidents · Bering Sea	1	24.2	1	24	new / 0
Other · Mediterranean Sea - Eastern Basin	1	22.5	1	22	0.8× / 1.2
Incidents · Tyrrhenian Sea	1	20.8	0	—	1.0× / 1
Cable ops · Tasman Sea	1	20.7	1	64	1.3× / 0.8
Surveys · Persian Gulf	1	19.6	1	19	1.7× / 0.6
Nav aids · Mediterranean Sea - Western Basin	1	18.3	0	—	1.0× / 1
Other · South Pacific Ocean	1	18.2	0	—	1.3× / 0.8
Surveys · Laccadive Sea	1	17	1	17	5.0× / 0.2
Wrecks · Laptev Sea	1	15.9	0	—	new / 0
Exercises · Gulf of Mexico	1	15.6	0	—	1.7× / 0.6
Exercises · Gulf of California	1	15.5	0	—	5.0× / 0.2
Incidents · Gulf of Mexico	1	13	1	77	5.0× / 0.2
Incidents · Bay of Biscay	1	12.9	1	12	2.5× / 0.4
Cable ops · Ceram Sea	1	12	1	11	new / 0
Surveys · North Atlantic Ocean	1	11.6	1	11	0.5× / 2
Cable ops · Mediterranean Sea - Eastern Basin	1	11.5	1	11	0.6× / 1.8
Cable ops · Norwegian Sea	1	11.4	1	11	2.5× / 0.4
Other · Bay of Bengal	1	5.5	1	5	new / 0
Missiles · Laccadive Sea	1	5.1	0	—	new / 0
Missiles · Bay of Bengal	1	4.9	0	—	5.0× / 0.2
Ordnance · Persian Gulf	1	4.2	0	—	5.0× / 0.2
Derelicts · South China Sea	1	3.6	1	3	1.0× / 1
Quakes · Aegean Sea	1	3	0	—	new / 0
Debris · Arafura Sea	1	3	0	—	5.0× / 0.2
Quakes · Banda Sea	1	3	0	—	0.6× / 1.8
Quakes · Caribbean Sea	1	3	0	—	new / 0
Quakes · Eastern China Sea	1	3	0	—	0.8× / 1.2
Quakes · Gulf of Mexico	1	3	0	—	new / 0
Debris · Indian Ocean	1	3	0	—	5.0× / 0.2
Quakes · Japan Sea	1	3	0	—	5.0× / 0.2
Quakes · Molukka Sea	1	3	0	—	1.0× / 1
Debris · North Atlantic Ocean	1	3	0	—	2.5× / 0.4
Derelicts · Philippine Sea	1	3	0	—	new / 0
Quakes · Philippine Sea	1	3	0	—	0.3× / 3.2
Derelicts · Tasman Sea	1	3	0	—	2.5× / 0.4
Debris · Timor Sea	1	3	0	—	new / 0
Derelicts · Timor Sea	1	3	0	—	2.5× / 0.4
Exercises · Gulf of Alaska	1	2.7	0	—	new / 0
Surveys · Tasman Sea	1	2.7	0	—	1.7× / 0.6
Surveys · Mediterranean Sea - Western Basin	1	2.5	0	—	5.0× / 0.2
Nav aids · Andaman or Burma Sea	1	2	0	—	new / 0
Incidents · Bismarck Sea	1	1.6	0	—	5.0× / 0.2
Mines · Mediterranean Sea - Eastern Basin	1	1.5	1	1	new / 0
Ordnance · Inner Seas off the West Coast of Scotland	1	0.9	0	—	new / 0
Quakes · Bismarck Sea	1	0.8	1	0	2.5× / 0.4
Derelicts · Coral Sea	1	0.8	0	—	5.0× / 0.2
Other · Inner Seas off the West Coast of Scotland	1	0.5	0	—	1.7× / 0.6
Incidents · Tasman Sea	1	0.5	0	—	0.5× / 2.2
Incidents · Philippine Sea	1	0.2	0	—	0.1× / 7.6
Incidents · Solomon Sea	1	0.2	0	—	new / 0
Nav aids · Coral Sea	1	0.1	0	—	0.4× / 2.4
Nav aids · Great Australian Bight	1	0.1	0	—	0.7× / 1.4
Incidents · Great Australian Bight	1	0.1	0	—	5.0× / 0.2
Surveys · Arctic Oceanlong running	0	660	22	2,669	0.0× / 0.2
Surveys · Beaufort Sealong running	0	330	11	2,669	— / 0
Exercises · Aegean Sea	0	150	5	121	0.0× / 2.6
Wrecks · The Northwestern Passages	0	119.3	3	302	— / 0
Nav aids · South Pacific Oceanlong running	0	107	1	471	0.0× / 1.4
Wrecks · South China Sea	0	91.5	3	221	— / 0
Surveys · Laptev Sealong running	0	90	3	1,803	— / 0
Surveys · Baffin Bay	0	60	2	302	— / 0
Surveys · Chukchi Sealong running	0	60	2	2,202	— / 0
Surveys · Davis Strait	0	60	2	116	— / 0
Wrecks · South Pacific Ocean	0	60	2	133	0.0× / 0.4
Other · Persian Gulf	0	50.4	1	256	— / 0
Missiles · Aegean Sea	0	30	1	121	— / 0
Wrecks · Arabian Sealong running	0	30	1	500	0.0× / 0.2
Other · Arctic Ocean	0	30	1	300	— / 0
Surveys · Bering Sea	0	30	1	259	— / 0
Cable ops · Caribbean Sea	0	30	1	260	0.0× / 0.6
Nav aids · Caribbean Sea	0	30	1	57	0.0× / 0.4
Surveys · Greenland Sealong running	0	30	1	2,985	— / 0
Surveys · Gulf of Aqaba	0	30	1	36	— / 0
Nav aids · Gulf of Suez	0	30	1	361	0.0× / 0.8
Structures · Indian Ocean	0	30	1	49	— / 0
Nav aids · Irish Sea and St. George's Channel	0	30	1	63	0.0× / 2.2
Nav aids · Mediterranean Sea - Eastern Basin	0	30	1	193	0.0× / 0.2
Cable ops · North Pacific Ocean	0	30	1	79	— / 0
Ordnance · North Sealong running	0	30	1	911	0.0× / 1.2
Structures · North Sea	0	30	1	81	0.0× / 0.4
Wrecks · North Sea	0	30	1	344	0.0× / 0.2
Restricted · Persian Gulf	0	30	1	149	— / 0
Wrecks · Persian Gulf	0	30	1	127	— / 0
Volcanic · Philippine Sealong running	0	30	1	428	0.0× / 0.8
Cable ops · Red Sea	0	30	1	54	— / 0
Nav aids · Red Sea	0	30	1	103	— / 0
Wrecks · South Atlantic Ocean	0	30	1	353	— / 0
Cable ops · South Pacific Ocean	0	30	1	35	0.0× / 1.6
Other · The Northwestern Passages	0	30	1	273	— / 0
Surveys · The Northwestern Passageslong running	0	30	1	967	— / 0
Incidents · Mozambique Channel	0	29.4	0	—	0.0× / 0.8
Nav aids · Indian Ocean	0	26.6	0	—	0.0× / 1.4
Surveys · Mozambique Channel	0	25.4	0	—	0.0× / 1.2
Incidents · Andaman or Burma Sea	0	18.5	0	—	0.0× / 0.4
Cable ops · Adriatic Sea	0	15.4	0	—	— / 0
Other · Gulf of Suez	0	12.3	0	—	0.0× / 0.2
Spills · North Pacific Ocean	0	12	0	—	0.0× / 1.8
Incidents · Arabian Sea	0	8.4	0	—	0.0× / 1
Incidents · Southern Ocean	0	8.4	0	—	0.0× / 0.2
Cable ops · Philippine Sea	0	6	0	—	0.0× / 0.6
Derelicts · Ionian Sea	0	1.4	0	—	0.0× / 0.2
Surveys · Irish Sea and St. George's Channel	0	1.4	0	—	0.0× / 0.2

Cite: seahazards.com Sea Ledger, 2011-04, retrieved 2026-09-03

Not for navigation. Warning-days = days each warning was in force within the month, summed. Only warnings we display are counted; the ratio compares warnings issued with the mean of the reference months.