Sea Ledger, January 2021

2021-01-01 to 2021-01-31 · archive

issued: 697
warning-days in force: 8,623
in force at month end: 287
sea × type cells: 210

baseline: same month, previous 5 years (2020-01, 2019-01, 2018-01, 2017-01, 2016-01)

By type

type	issued	warning-days	in force at end
Exercises	161	1,404.2	46
Incidents	141	1,206.9	34
Icebergs	91	101	3
Surveys	70	1,376	51
Missiles	53	215.4	15
Nav aids	50	1,620	56
Quakes	31	92.4	3
Derelicts	28	200.9	5
Cable ops	21	568.2	15
Other	12	261.8	8
Piracy	10	59.6	2
Debris	10	27.6	0
Wrecks	7	1,058.3	36
Spills	4	85	3
Containers	3	9	0
Structures	2	49.7	1
Mines	2	59.2	2
Restricted	1	103.5	3
Ordnance	0	31	1
Volcanic	0	93	3

By sea and type · 200 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Incidents · South China Sea	40	324.9	6	357	1.5× / 26.6
Icebergs · Labrador Sea	31	36.2	2	32	1.1× / 29
Icebergs · South Atlantic Ocean	31	31	1	31	1.3× / 24.8
Exercises · North Pacific Ocean	29	244	10	66	1.3× / 21.8
Icebergs · Southern Ocean	27	27.8	0	—	1.8× / 15
Surveys · South Atlantic Ocean	23	213.2	7	60	1.5× / 15.2
Exercises · Aegean Sealong running	21	196.8	9	398	1.4× / 14.6
Exercises · Arabian Seasurge	20	110.2	5	34	2.3× / 8.8
Exercises · Black Sea	14	295.6	10	65	1.4× / 10
Exercises · Bay of Bengal	13	126	3	30	1.6× / 8.2
Missiles · Indian Oceansurge	13	20.8	3	18	4.3× / 3
Exercises · Mediterranean Sea - Eastern Basinlong running	12	58.5	2	395	0.8× / 15.4
Missiles · North Atlantic Oceansurge	12	19.5	2	27	2.0× / 6
Nav aids · North Atlantic Oceanlong running	11	222.4	9	540	1.4× / 7.6
Incidents · Laccadive Seasurge	11	87.8	3	45	7.9× / 1.4
Incidents · North Pacific Ocean	9	108.9	2	38	0.5× / 18
Incidents · Java Seasurge	9	107.2	2	328	7.5× / 1.2
Nav aids · North Sea	9	74.3	4	126	0.8× / 12
Incidents · North Atlantic Ocean	9	67.6	3	24	0.7× / 13.4
Exercises · North Atlantic Ocean	9	61.8	0	—	1.2× / 7.4
Incidents · Arabian Sea	8	70.8	1	28	1.9× / 4.2
Missiles · Black Sea	8	53.6	6	32	1.7× / 4.8
Incidents · Philippine Sea	8	52.5	2	27	1.2× / 6.6
Missiles · South Pacific Oceansurge	8	36.9	0	—	3.1× / 2.6
Quakes · South Pacific Ocean	8	24	0	—	0.8× / 9.8
Nav aids · South Atlantic Ocean	7	123.1	6	97	0.8× / 8.6
Surveys · Persian Gulfsurgelong running	7	107.8	4	614	2.9× / 2.4
Surveys · Indian Oceansurge	7	58.6	2	29	3.5× / 2
Incidents · Mediterranean Sea - Eastern Basin	7	51.5	4	23	0.4× / 16.2
Incidents · South Atlantic Ocean	7	43.6	3	34	1.5× / 4.8
Exercises · South Atlantic Ocean	7	38.5	1	21	0.7× / 10.8
Surveys · Mediterranean Sea - Eastern Basin	6	158.8	7	88	1.5× / 4
Exercises · Yellow Sea	6	48.4	1	31	1.1× / 5.6
Piracy · Gulf of Guineasurge	6	36.6	1	33	2.3× / 2.6
Exercises · South Pacific Ocean	6	16.6	0	—	1.1× / 5.4
Surveys · Arabian Sea	5	112.2	4	55	0.7× / 7
Missiles · Barentsz Seasurge	5	38.3	2	25	3.6× / 1.4
Incidents · Indian Ocean	5	29	1	39	1.0× / 5.2
Derelicts · Arafura Seasurge	5	17.2	0	—	13× / 0.4
Cable ops · North Atlantic Ocean	4	63.7	1	51	1.2× / 3.4
Exercises · Ionian Seasurge	4	58.6	3	19	2.9× / 1.4
Nav aids · Inner Seas off the West Coast of Scotlandlong running	4	45.9	1	416	1.7× / 2.4
Incidents · Gulf of Mexico	4	38.3	3	27	1.4× / 2.8
Exercises · Andaman or Burma Seasurge	4	15.9	0	—	6.7× / 0.6
Quakes · North Pacific Ocean	4	11.2	2	33	0.7× / 5.4
Derelicts · North Atlantic Ocean	4	10.9	1	16	0.7× / 5.6
Debris · North Atlantic Oceansurge	4	9.6	0	—	3.3× / 1.2
Surveys · North Atlantic Ocean	3	264.9	7	359	0.9× / 3.2
Nav aids · South Pacific Oceanlong running	3	246.9	6	818	1.5× / 2
Derelicts · Arabian Sealong running	3	87.4	3	373	1.9× / 1.6
Derelicts · Caribbean Sea	3	40	0	—	1.3× / 2.4
Exercises · Laccadive Sea	3	39.6	1	33	1.5× / 2
Other · Gulf of Mexicosurge	3	38.6	2	20	7.5× / 0.4
Incidents · Caribbean Sea	3	24.1	1	26	0.9× / 3.4
Missiles · North Pacific Ocean	3	17.4	1	16	0.4× / 7.4
Nav aids · Coral Sea	3	15.1	0	—	0.8× / 3.8
Other · North Pacific Oceansurge	3	14.4	1	30	3.0× / 1
Exercises · Barentsz Seasurge	3	13.7	0	—	7.5× / 0.4
Quakes · South Atlantic Oceansurge	3	10	0	—	3.0× / 1
Derelicts · North Pacific Ocean	3	9	0	—	0.8× / 3.6
Derelicts · Tasman Sea	3	8.9	1	25	1.5× / 2
Exercises · Mediterranean Sea - Western Basinsurge	3	8.5	0	—	2.5× / 1.2
Incidents · Bismarck Sea	3	6.8	0	—	1.0× / 3
Incidents · Arafura Seasurge	3	0.3	0	—	2.5× / 1.2
Nav aids · North Pacific Oceanlong running	2	67.9	3	548	0.5× / 4
Incidents · South Pacific Ocean	2	56.4	0	—	0.3× / 6.2
Cable ops · North Pacific Oceannew	2	53.4	2	152	new / 0
Wrecks · South Atlantic Oceannew	2	49.4	3	188	new / 0
Surveys · Barentsz Seanew	2	47.3	2	104	new / 0
Surveys · Laccadive Sea	2	44.6	1	32	2.0× / 1
Cable ops · Arabian Sea	2	34.9	2	31	1.7× / 1.2
Surveys · Mediterranean Sea - Western Basin	2	22.3	2	18	10× / 0.2
Incidents · Bay of Bengal	2	21.1	1	41	3.3× / 0.6
Exercises · Japan Sea	2	20.3	0	—	2.5× / 0.8
Spills · North Pacific Ocean	2	18	2	11	0.8× / 2.6
Piracy · Caribbean Seanew	2	14	0	—	new / 0
Cable ops · Irish Sea and St. George's Channel	2	12.9	0	—	3.3× / 0.6
Cable ops · Philippine Sea	2	12.4	0	—	10× / 0.2
Surveys · Bass Strait	2	7.4	2	4	5.0× / 0.4
Exercises · Caribbean Sea	2	6.3	0	—	1.3× / 1.6
Quakes · Coral Sea	2	6	0	—	1.1× / 1.8
Icebergs · Laptev Seanew	2	6	0	—	new / 0
Quakes · Makassar Straitnew	2	6	0	—	new / 0
Containers · North Pacific Ocean	2	6	0	—	2.5× / 0.8
Quakes · Solomon Sea	2	6	0	—	0.9× / 2.2
Derelicts · South Pacific Ocean	2	6	0	—	1.0× / 2
Quakes · Southern Ocean	2	6	0	—	10× / 0.2
Debris · Timor Seanew	2	6	0	—	new / 0
Surveys · Strait of Gibraltarnew	2	5.4	0	—	new / 0
Quakes · Indian Ocean	2	5.2	1	25	1.0× / 2
Surveys · North Sea	2	4.9	0	—	1.7× / 1.2
Derelicts · Philippine Sea	2	4.9	0	—	2.5× / 0.8
Incidents · Solomon Sea	2	4.5	0	—	2.5× / 0.8
Other · The Coastal Waters of Southeast Alaska and British Columbianew	2	2.9	0	—	new / 0
Incidents · Great Australian Bight	2	0.2	0	—	2.0× / 1
Wrecks · South China Sealong running	1	279.1	9	714	0.6× / 1.6
Nav aids · Mediterranean Sea - Western Basin	1	98.3	4	245	0.6× / 1.6
Nav aids · Gulf of Mexico	1	88.2	2	76	0.3× / 3.8
Surveys · Black Sea	1	85.5	3	228	new / 0
Nav aids · Persian Gulf	1	74.3	3	291	5.0× / 0.2
Cable ops · Aegean Sea	1	64	2	89	new / 0
Wrecks · North Pacific Oceanlong running	1	48.6	2	668	new / 0
Cable ops · Persian Gulf	1	46.2	1	70	1.0× / 1
Exercises · Indian Ocean	1	39.1	1	39	0.4× / 2.6
Incidents · Gulf of Thailand	1	36.1	0	—	1.0× / 1
Nav aids · Mozambique Channel	1	35.6	2	109	new / 0
Surveys · South Pacific Oceanlong running	1	34.8	2	487	1.3× / 0.8
Nav aids · Arabian Sealong running	1	34.5	1	451	0.6× / 1.8
Nav aids · Andaman or Burma Sealong running	1	31	1	612	2.5× / 0.4
Cable ops · Black Sea	1	31	1	144	5.0× / 0.2
Mines · English Channel	1	31	1	58	new / 0
Wrecks · English Channel	1	31	1	65	1.7× / 0.6
Surveys · Mozambique Channel	1	31	1	41	5.0× / 0.2
Nav aids · Norwegian Sea	1	31	1	44	5.0× / 0.2
Cable ops · Malacca Strait	1	29.5	1	29	new / 0
Mines · Persian Gulf	1	28.2	1	28	new / 0
Cable ops · Eastern China Sea	1	26	1	37	1.0× / 1
Nav aids · English Channel	1	24.2	1	24	0.3× / 3
Cable ops · Andaman or Burma Sea	1	23.3	0	—	2.5× / 0.4
Cable ops · South Pacific Ocean	1	23.2	0	—	0.8× / 1.2
Spills · Caribbean Sea	1	21	0	—	new / 0
Nav aids · Bering Sea	1	20.7	0	—	2.5× / 0.4
Cable ops · South Atlantic Ocean	1	20.7	1	32	0.3× / 3.6
Wrecks · Southern Ocean	1	20.4	1	20	new / 0
Missiles · Aegean Sea	1	19.4	1	239	2.5× / 0.4
Structures · Arabian Sea	1	17.3	0	—	new / 0
Surveys · Bay of Bengal	1	17.3	1	65	0.4× / 2.8
Surveys · Celtic Sea	1	16.3	1	16	2.5× / 0.4
Wrecks · Japan Sea	1	16.1	1	37	new / 0
Spills · Gulf of Mexico	1	16	1	42	0.2× / 5.2
Incidents · Makassar Strait	1	15.5	1	15	new / 0
Incidents · Mediterranean Sea - Western Basin	1	14.6	0	—	1.0× / 1
Incidents · Andaman or Burma Sea	1	12.9	1	12	5.0× / 0.2
Surveys · Gulf of Mexico	1	11.1	0	—	2.5× / 0.4
Restricted · Japan Sea	1	10.5	0	—	new / 0
Cable ops · Gulf of Guinea	1	7	0	—	5.0× / 0.2
Piracy · South Atlantic Ocean	1	7	0	—	new / 0
Other · North Atlantic Ocean	1	6.5	0	—	0.6× / 1.6
Exercises · Red Sea	1	5	0	—	5.0× / 0.2
Missiles · Arabian Sea	1	4.2	0	—	1.0× / 1
Missiles · Laccadive Sea	1	3.9	0	—	0.6× / 1.6
Other · Great Australian Bight	1	3.6	1	3	new / 0
Debris · Arafura Sea	1	3	0	—	5.0× / 0.2
Nav aids · Bass Strait	1	3	0	—	1.0× / 1
Quakes · Flores Sea	1	3	0	—	new / 0
Derelicts · Great Australian Bight	1	3	0	—	new / 0
Quakes · Gulf of Tomini	1	3	0	—	new / 0
Debris · Indian Ocean	1	3	0	—	2.5× / 0.4
Other · Indian Ocean	1	3	0	—	2.5× / 0.4
Quakes · Japan Sea	1	3	0	—	5.0× / 0.2
Derelicts · Laccadive Sea	1	3	0	—	1.0× / 1
Debris · North Pacific Ocean	1	3	0	—	1.0× / 1
Quakes · Persian Gulf	1	3	0	—	new / 0
Quakes · Philippine Sea	1	3	0	—	0.5× / 2
Quakes · Sea of Okhotsk	1	3	0	—	5.0× / 0.2
Containers · South Atlantic Ocean	1	3	0	—	new / 0
Derelicts · South China Sea	1	3	0	—	0.4× / 2.8
Debris · South Pacific Ocean	1	3	0	—	1.7× / 0.6
Piracy · Singapore Strait	1	2	1	1	new / 0
Incidents · Coral Sea	1	1.5	0	—	0.2× / 4.6
Missiles · Gulf of Mexico	1	1.4	0	—	new / 0
Structures · South Atlantic Ocean	1	1.4	0	—	2.5× / 0.4
Other · Bering Sea	1	1.2	0	—	1.7× / 0.6
Nav aids · Arafura Sea	1	1.1	0	—	1.7× / 0.6
Surveys · Tyrrhenian Sea	1	1	1	0	new / 0
Exercises · Bay of Biscay	1	0.8	0	—	new / 0
Incidents · Eastern China Sea	1	0.2	0	—	1.3× / 0.8
Incidents · Timor Sea	1	0.1	0	—	1.7× / 0.6
Wrecks · Persian Gulflong running	0	303.7	9	578	0.0× / 1.2
Nav aids · Caribbean Sea	0	248	8	111	0.0× / 2.4
Wrecks · North Atlantic Oceanlong running	0	124	4	741	0.0× / 0.6
Other · Persian Gulf	0	82.7	2	209	— / 0
Wrecks · Arabian Sealong running	0	62	2	495	0.0× / 0.8
Surveys · Arctic Ocean	0	62	2	104	— / 0
Wrecks · Inner Seas off the West Coast of Scotland	0	62	2	114	0.0× / 0.2
Volcanic · Philippine Sea	0	62	2	44	— / 0
Restricted · South Atlantic Oceanlong running	0	62	2	395	0.0× / 0.6
Other · South Pacific Ocean	0	60.9	1	318	0.0× / 0.8
Nav aids · Bay of Bengal	0	34.5	1	235	0.0× / 0.8
Nav aids · Alboran Sea	0	31	1	129	— / 0
Surveys · Bering Sea	0	31	1	102	— / 0
Cable ops · Caribbean Sea	0	31	1	65	0.0× / 0.2
Nav aids · Gulf of Thailandlong running	0	31	1	472	0.0× / 0.2
Cable ops · Indian Ocean	0	31	1	36	0.0× / 0.4
Cable ops · Mediterranean Sea - Eastern Basin	0	31	1	60	0.0× / 1
Nav aids · Mediterranean Sea - Eastern Basin	0	31	1	178	— / 0
Other · Mediterranean Sea - Eastern Basin	0	31	1	129	0.0× / 0.8
Volcanic · Mozambique Channellong running	0	31	1	486	— / 0
Wrecks · Mozambique Channel	0	31	1	109	— / 0
Ordnance · North Sealong running	0	31	1	475	0.0× / 1.2
Restricted · Persian Gulflong running	0	31	1	655	0.0× / 0.2
Wrecks · Red Sealong running	0	31	1	414	— / 0
Structures · South China Sealong running	0	31	1	433	— / 0
Surveys · South China Sealong running	0	31	1	507	0.0× / 0.2
Cable ops · Mediterranean Sea - Western Basin	0	19	0	—	0.0× / 1.4
Incidents · Bass Strait	0	14.6	0	—	0.0× / 0.2
Other · Davis Strait	0	12.8	0	—	— / 0
Spills · North Atlantic Ocean	0	12	0	—	0.0× / 2
Spills · The Coastal Waters of Southeast Alaska and British Columbia	0	10	0	—	0.0× / 0.4
Incidents · Celebes Sea	0	8.3	0	—	0.0× / 0.2

Cite: seahazards.com Sea Ledger, 2021-01, 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.