Sea Ledger, August 2011

2011-08-01 to 2011-08-31 · archive

issued: 418
warning-days in force: 6,241
in force at month end: 207
sea × type cells: 181

baseline: same month, previous 5 years (2010-08, 2009-08, 2008-08, 2007-08, 2006-08)

By type

type	issued	warning-days	in force at end
Incidents	87	668.8	19
Exercises	63	649.8	21
Nav aids	57	1,190.7	40
Cable ops	50	950.3	36
Quakes	47	146.1	4
Missiles	29	244.2	5
Surveys	19	1,052.9	34
Derelicts	17	45	0
Piracy	10	78.1	1
Containers	9	25.9	1
Spills	8	72	6
Other	6	333.3	11
Restricted	5	69.4	3
Wrecks	4	457.3	17
Debris	2	4.9	0
Ordnance	2	38.9	2
Structures	2	55.1	2
Icebergs	1	3	0
War risk	0	124	4
Volcanic	0	31	1

By sea and type · 181 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Incidents · North Pacific Oceansurge	29	166.9	3	60	2.6× / 11
Exercises · North Pacific Ocean	16	53.8	2	30	1.5× / 10.6
Missiles · North Pacific Oceansurge	15	109.6	2	37	2.6× / 5.8
Incidents · South China Seasurge	14	123.4	3	32	5.8× / 2.4
Quakes · South Pacific Ocean	13	41.9	0	—	1.2× / 10.6
Cable ops · North Atlantic Oceansurge	12	151.5	5	64	2.1× / 5.6
Quakes · Coral Seasurge	11	32.2	1	23	4.2× / 2.6
Containers · North Pacific Oceannew	9	25.9	1	30	new / 0
Nav aids · South Atlantic Oceanlong running	8	349.9	13	1,106	1.4× / 5.6
Exercises · South China Seasurge	8	139.8	4	42	5.7× / 1.4
Cable ops · South Atlantic Oceanlong running	8	86.2	4	1,026	0.4× / 19
Quakes · North Pacific Ocean	8	28.5	0	—	1.4× / 5.8
Cable ops · South China Sea	7	121.4	7	141	1.8× / 4
Cable ops · Persian Gulfsurge	6	137.4	4	231	7.5× / 0.8
Nav aids · North Atlantic Oceansurgelong running	6	63.3	1	456	3.0× / 2
Incidents · Bay of Bengalsurge	6	47	1	29	5.0× / 1.2
Nav aids · Coral Seasurge	6	33.4	1	68	2.7× / 2.2
Exercises · South Atlantic Ocean	6	32.9	2	34	1.3× / 4.8
Derelicts · North Pacific Oceansurge	6	15.6	0	—	4.3× / 1.4
Nav aids · South Pacific Oceansurge	5	111.4	3	188	5.0× / 1
Nav aids · Irish Sea and St. George's Channelsurge	5	59.9	2	87	2.3× / 2.2
Incidents · South Pacific Ocean	5	57.1	2	64	0.5× / 10.8
Exercises · Yellow Sea	5	38.5	2	35	1.4× / 3.6
Exercises · Bay of Bengal	5	32.4	2	28	1.1× / 4.6
Exercises · South Pacific Ocean	5	22.2	0	—	1.6× / 3.2
Nav aids · North Sea	5	16.9	0	—	1.0× / 5
Exercises · Philippine Sea	4	71.5	2	35	0.9× / 4.4
Exercises · Laccadive Sea	4	38.9	1	33	0.8× / 5.2
Spills · North Atlantic Oceansurge	4	37	2	26	2.0× / 2
Restricted · North Seasurge	4	30.5	2	31	20× / 0.2
Missiles · Barentsz Seanew	4	27.3	0	—	new / 0
Nav aids · Celtic Seasurge	4	23.6	1	23	2.9× / 1.4
Derelicts · Arafura Seanew	4	12	0	—	new / 0
Quakes · South Atlantic Oceansurge	4	12	0	—	2.0× / 2
Exercises · Indian Oceansurge	4	8.9	0	—	2.2× / 1.8
Incidents · Coral Sea	4	4.6	0	—	1.2× / 3.4
Nav aids · North Pacific Oceansurge	3	107.8	4	247	5.0× / 0.6
Incidents · South Atlantic Ocean	3	70.6	1	35	0.6× / 5
Surveys · Black Seasurge	3	66.8	2	56	7.5× / 0.4
Surveys · The Northwestern Passagessurge	3	37.4	2	18	3.0× / 1
Spills · Gulf of Mexico	3	34	3	13	0.6× / 4.8
Piracy · Red Seasurge	3	26.2	0	—	15× / 0.2
Piracy · Gulf of Aden	3	22.6	1	22	1.1× / 2.8
Incidents · Mediterranean Sea - Eastern Basin	3	20.5	1	28	1.5× / 2
Piracy · Arabian Seanew	3	20.3	0	—	new / 0
Incidents · Gulf of Mexicosurge	3	12.4	1	21	15× / 0.2
Nav aids · Tasman Seasurge	3	12.3	1	13	2.1× / 1.4
Quakes · Bismarck Seasurge	3	12	0	—	3.0× / 1
Surveys · North Atlantic Oceansurge	3	9.4	0	—	2.1× / 1.4
Incidents · Arabian Seasurge	3	6.7	2	10	2.5× / 1.2
Incidents · Indian Oceansurge	3	1.5	0	—	3.0× / 1
Wrecks · Arabian Seanewlong running	2	142.6	6	623	new / 0
Nav aids · Hudson Baynew	2	43	2	21	new / 0
Exercises · Arabian Sea	2	38.5	1	35	0.8× / 2.4
Cable ops · Mediterranean Sea - Eastern Basin	2	38.1	2	33	1.3× / 1.6
Incidents · Philippine Sea	2	28.4	0	—	0.3× / 6
Missiles · North Atlantic Ocean	2	27.5	0	—	10× / 0.2
Cable ops · Gulf of Guinea	2	25.1	2	15	5.0× / 0.4
Cable ops · Labrador Seanew	2	15.6	1	16	new / 0
Nav aids · Mediterranean Sea - Western Basin	2	14.4	1	14	5.0× / 0.4
Cable ops · Celtic Sea	2	8	0	—	2.5× / 0.8
Cable ops · Coral Seanew	2	8	0	—	new / 0
Nav aids · Gulf of Alaska	2	7.6	0	—	1.7× / 1.2
Derelicts · Indian Ocean	2	6	0	—	2.0× / 1
Quakes · Indian Ocean	2	6	0	—	0.7× / 2.8
Derelicts · Tasman Seanew	2	4.1	0	—	new / 0
Derelicts · Philippine Sea	2	4	0	—	2.5× / 0.8
Quakes · North Atlantic Ocean	2	3.5	1	8	2.5× / 0.8
Other · Davis Straitnew	2	0.7	0	—	new / 0
Incidents · Tasman Sea	2	0.3	0	—	1.7× / 1.2
Surveys · Arctic Oceanlong running	1	279	9	425	5.0× / 0.2
Cable ops · Norwegian Sea	1	78.9	3	60	1.3× / 0.8
Wrecks · The Northwestern Passageslong running	1	70.8	3	425	new / 0
Surveys · South Atlantic Ocean	1	61.1	2	88	0.4× / 2.6
Cable ops · North Sea	1	58	1	47	0.6× / 1.8
Structures · North Sea	1	47.1	2	41	5.0× / 0.2
Other · The Northwestern Passageslong running	1	42.8	1	396	new / 0
Surveys · Sea of Okhotsk	1	36.5	1	40	0.8× / 1.2
Incidents · Tyrrhenian Sea	1	34.6	1	60	2.5× / 0.4
Cable ops · Gulf of Mexico	1	33.8	1	99	1.3× / 0.8
Cable ops · Sea of Okhotsk	1	30.5	1	51	1.7× / 0.6
Nav aids · Beaufort Sea	1	27.9	0	—	5.0× / 0.2
Incidents · Laccadive Sea	1	27.8	1	31	new / 0
Cable ops · Mozambique Channel	1	25.3	1	25	5.0× / 0.2
Surveys · Caribbean Sea	1	22.6	1	22	5.0× / 0.2
Incidents · Malacca Strait	1	21.1	0	—	new / 0
Incidents · Adriatic Sea	1	17.7	1	17	2.5× / 0.4
Nav aids · South China Sea	1	16.7	1	16	new / 0
Surveys · Mediterranean Sea - Eastern Basin	1	14.6	0	—	2.5× / 0.4
Missiles · Japan Sea	1	13.2	0	—	new / 0
Surveys · Barentsz Sea	1	12.8	1	44	new / 0
Wrecks · North Atlantic Ocean	1	12.2	1	12	new / 0
Missiles · Laccadive Sea	1	11.8	0	—	new / 0
Missiles · Southern Ocean	1	11.4	0	—	new / 0
Incidents · Andaman or Burma Sea	1	10.5	1	10	2.5× / 0.4
Piracy · South China Sea	1	9	0	—	0.5× / 2.2
Structures · Mediterranean Sea - Eastern Basin	1	8	0	—	5.0× / 0.2
Restricted · North Atlantic Ocean	1	7.9	0	—	2.5× / 0.4
Surveys · Irish Sea and St. George's Channel	1	7	0	—	5.0× / 0.2
Surveys · Tasman Sea	1	6.3	0	—	new / 0
Exercises · Japan Sea	1	6	0	—	0.2× / 4.8
Ordnance · Kara Sea	1	5.3	1	5	new / 0
Exercises · Andaman or Burma Sea	1	4.8	0	—	1.3× / 0.8
Quakes · Philippine Sea	1	4.7	0	—	0.2× / 4.2
Incidents · Arafura Sea	1	4.6	0	—	2.5× / 0.4
Surveys · Japan Sea	1	4.6	1	4	new / 0
Missiles · South Pacific Ocean	1	4.6	1	4	new / 0
Other · Arabian Sea	1	4	0	—	5.0× / 0.2
Cable ops · Indian Ocean	1	3.9	0	—	2.5× / 0.4
Exercises · Coral Sea	1	3.7	0	—	1.7× / 0.6
Surveys · Aegean Sea	1	3.4	0	—	5.0× / 0.2
Incidents · Bismarck Sea	1	3.3	0	—	new / 0
Derelicts · Coral Sea	1	3.3	0	—	new / 0
Quakes · Ceram Sea	1	3	0	—	5.0× / 0.2
Icebergs · Indian Ocean	1	3	0	—	new / 0
Debris · North Pacific Ocean	1	3	0	—	5.0× / 0.2
Exercises · Bering Sea	1	2.9	0	—	2.5× / 0.4
Missiles · Malacca Strait	1	2.6	0	—	new / 0
Ordnance · South China Sea	1	2.6	0	—	new / 0
Cable ops · Strait of Gibraltar	1	2.6	0	—	new / 0
Missiles · Indian Ocean	1	2	0	—	new / 0
Missiles · Philippine Sea	1	2	0	—	1.7× / 0.6
Debris · Bismarck Sea	1	1.9	0	—	new / 0
Incidents · Solomon Sea	1	1.9	0	—	5.0× / 0.2
Incidents · Gulf of Thailand	1	1.8	1	1	5.0× / 0.2
Quakes · Banda Sea	1	1.7	1	1	1.0× / 1
Nav aids · Sea of Okhotsk	1	1.4	1	1	new / 0
Other · Inner Seas off the West Coast of Scotland	1	1.2	0	—	5.0× / 0.2
Missiles · Kara Sea	1	1.2	1	1	new / 0
Spills · North Pacific Ocean	1	1	1	1	0.5× / 2
Incidents · Mozambique Channel	1	0.7	0	—	1.0× / 1
Quakes · Solomon Sea	1	0.6	1	0	0.8× / 1.2
Nav aids · Black Sea	1	0.3	1	0	new / 0
Other · Kara Sea	1	0.2	1	0	new / 0
Nav aids · Indian Ocean	1	0.1	0	—	0.4× / 2.4
Nav aids · Inner Seas off the West Coast of Scotland	1	0	0	—	0.7× / 1.4
Exercises · Aegean Sea	0	155	5	244	— / 0
Surveys · Beaufort Sealong running	0	124	4	425	0.0× / 0.2
War risk · Mediterranean Sea - Eastern Basin	0	124	4	98	— / 0
Nav aids · Arabian Sealong running	0	93	3	390	0.0× / 0.8
Surveys · Baffin Baylong running	0	93	3	425	— / 0
Wrecks · South China Sea	0	93	3	344	0.0× / 0.2
Surveys · Chukchi Sea	0	62	2	353	— / 0
Nav aids · Gulf of Mexico	0	62	2	151	0.0× / 1.8
Other · North Pacific Ocean	0	62	2	86	0.0× / 1
Nav aids · Caribbean Sea	0	57.4	1	99	0.0× / 0.2
Missiles · Aegean Sea	0	31	1	244	— / 0
Other · Arctic Ocean	0	31	1	55	0.0× / 0.4
Cable ops · Barentsz Sea	0	31	1	92	— / 0
Other · Bay of Bengal	0	31	1	128	— / 0
Surveys · Bering Sealong running	0	31	1	382	0.0× / 0.2
Surveys · Davis Strait	0	31	1	103	— / 0
Cable ops · Gulf of Thailand	0	31	1	34	— / 0
Wrecks · Laccadive Sea	0	31	1	152	0.0× / 0.2
Nav aids · Mediterranean Sea - Eastern Basin	0	31	1	316	— / 0
Other · Mediterranean Sea - Eastern Basin	0	31	1	145	0.0× / 0.8
Surveys · Mozambique Channel	0	31	1	69	0.0× / 0.2
Surveys · North Pacific Ocean	0	31	1	61	0.0× / 0.4
Ordnance · North Sealong running	0	31	1	1,034	— / 0
Other · North Sea	0	31	1	177	0.0× / 2.2
Surveys · North Sea	0	31	1	162	0.0× / 1.8
Restricted · Persian Gulf	0	31	1	272	— / 0
Surveys · Persian Gulf	0	31	1	112	0.0× / 0.2
Wrecks · Persian Gulf	0	31	1	250	— / 0
Volcanic · Philippine Sealong running	0	31	1	551	0.0× / 0.2
Nav aids · Red Sea	0	31	1	226	— / 0
Cable ops · Sea of Marmara	0	31	1	63	0.0× / 0.2
Other · Sea of Okhotsk	0	31	1	75	0.0× / 0.2
Other · South Atlantic Ocean	0	31	1	111	— / 0
Wrecks · South Atlantic Oceanlong running	0	31	1	476	— / 0
Other · South China Sealong running	0	31	1	1,141	0.0× / 1
Cable ops · South Pacific Ocean	0	31	1	99	0.0× / 0.2
Wrecks · South Pacific Ocean	0	31	1	180	0.0× / 0.2
Nav aids · English Channel	0	26.4	0	—	0.0× / 1.6
Surveys · Indian Ocean	0	26.4	0	—	0.0× / 0.2
Wrecks · English Channel	0	14.7	0	—	0.0× / 0.8
Incidents · Gulf of Aden	0	5.4	0	—	— / 0
Other · Yellow Sea	0	5.4	0	—	— / 0
Cable ops · Caribbean Sea	0	1	0	—	0.0× / 0.8
Cable ops · Mediterranean Sea - Western Basin	0	1	0	—	0.0× / 0.8
Missiles · South Atlantic Ocean	0	0	0	—	0.0× / 0.2

Cite: seahazards.com Sea Ledger, 2011-08, 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.