Sea Ledger, March 2021

2021-03-01 to 2021-03-31 · archive

issued: 701
warning-days in force: 10,181
in force at month end: 305
sea × type cells: 214

baseline: same month, previous 5 years (2020-03, 2019-03, 2018-03, 2017-03, 2016-03)

By type

type	issued	warning-days	in force at end
Exercises	172	1,694.3	53
Icebergs	93	102.7	4
Quakes	88	263.6	1
Incidents	74	938.4	18
Surveys	72	1,844.9	56
Nav aids	57	2,272.7	74
Missiles	53	452.5	8
Cable ops	29	522.9	16
Derelicts	19	114.2	6
Other	12	249	11
Spills	12	187	6
Wrecks	7	1,125.7	38
Debris	7	17	2
Structures	2	61.9	2
Piracy	2	14	0
Ordnance	1	66	2
Containers	1	3	0
Restricted	0	96.5	3
Mines	0	62	2
Volcanic	0	93	3

By sea and type · 200 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Quakes · South Pacific Oceansurge	63	188.1	1	32	8.8× / 7.2
Icebergs · Labrador Sea	31	36.6	2	32	1.9× / 16.6
Icebergs · South Atlantic Ocean	31	31.1	1	31	1.9× / 16.6
Icebergs · Southern Ocean	29	29	1	31	1.2× / 23.6
Exercises · North Pacific Ocean	27	172.8	7	63	1.1× / 24.2
Exercises · Black Sea	23	432.2	11	124	1.7× / 13.4
Surveys · South Atlantic Ocean	23	271.1	8	119	1.1× / 21.6
Incidents · South China Sea	19	252.1	5	359	0.6× / 31.2
Exercises · Arabian Seasurge	19	141.3	5	51	2.5× / 7.6
Missiles · Indian Oceansurge	16	60.4	0	—	10× / 1.6
Missiles · North Atlantic Ocean	15	41.4	0	—	1.6× / 9.2
Exercises · Aegean Sea	13	235.2	9	78	0.8× / 15.6
Exercises · Mediterranean Sea - Eastern Basin	13	90.7	2	33	0.7× / 19.8
Exercises · South Pacific Ocean	12	53.9	3	29	1.9× / 6.4
Surveys · Arabian Sea	9	229.9	6	56	1.2× / 7.6
Incidents · North Pacific Ocean	9	131.1	0	—	0.5× / 17.6
Exercises · Bay of Bengal	9	73.7	1	33	1.0× / 9.4
Surveys · Persian Gulfsurge	8	145.1	4	72	2.7× / 3
Nav aids · North Sea	8	135.7	5	185	0.6× / 13.6
Cable ops · North Pacific Oceansurge	8	112.3	5	211	40× / 0.2
Incidents · Arabian Seasurge	8	106.2	2	51	2.0× / 4
Exercises · Yellow Sea	8	54.2	1	34	1.4× / 5.8
Surveys · North Atlantic Oceansurge	7	236	10	152	2.2× / 3.2
Nav aids · Inner Seas off the West Coast of Scotlandlong running	7	78.2	1	475	1.8× / 3.8
Missiles · Japan Seasurge	7	48.5	3	33	3.5× / 2
Exercises · Caribbean Seasurge	7	18.3	0	—	2.5× / 2.8
Quakes · North Pacific Ocean	7	18	0	—	1.5× / 4.8
Exercises · Philippine Sea	7	17.8	0	—	0.8× / 8.4
Surveys · Black Seasurge	6	163	5	145	5.0× / 1.2
Exercises · South Atlantic Ocean	6	79.1	4	56	0.8× / 7.8
Exercises · North Atlantic Ocean	6	55	3	55	1.1× / 5.4
Cable ops · North Atlantic Ocean	6	44.4	1	56	1.9× / 3.2
Cable ops · Mediterranean Sea - Western Basinsurge	6	35	2	32	5.0× / 1.2
Nav aids · Coral Sea	6	31.8	1	28	0.9× / 7
Exercises · Andaman or Burma Seasurge	6	27.4	0	—	5.0× / 1.2
Nav aids · North Atlantic Oceanlong running	5	283.6	9	599	1.9× / 2.6
Nav aids · South Atlantic Ocean	5	251.1	5	156	0.6× / 8.8
Missiles · Black Sea	5	192.9	3	33	1.4× / 3.6
Incidents · North Atlantic Ocean	5	79.3	3	38	0.4× / 11.4
Incidents · South Pacific Ocean	5	68.7	0	—	0.8× / 6.6
Incidents · Laccadive Seasurge	4	56.5	2	25	3.3× / 1.2
Missiles · Barentsz Sea	4	36.7	1	35	1.3× / 3
Exercises · Mediterranean Sea - Western Basin	4	33	0	—	1.8× / 2.2
Exercises · Red Seasurge	4	21.3	1	26	20× / 0.2
Surveys · Aegean Seasurge	4	17.6	1	43	3.3× / 1.2
Incidents · South Atlantic Ocean	4	14.7	1	35	0.7× / 5.6
Derelicts · Caribbean Seasurge	4	7.8	1	13	2.0× / 2
Nav aids · North Pacific Oceanlong running	3	169.8	6	607	1.5× / 2
Cable ops · Arabian Seasurge	3	82.4	2	72	2.1× / 1.4
Spills · North Pacific Ocean	3	57	1	43	1.5× / 2
Spills · North Atlantic Ocean	3	50	2	37	0.9× / 3.4
Spills · Gulf of Mexico	3	32	2	15	0.8× / 3.6
Exercises · Japan Seasurge	3	29.1	0	—	2.5× / 1.2
Nav aids · English Channel	3	22.4	1	32	1.1× / 2.8
Incidents · Philippine Sea	3	21.5	1	40	0.7× / 4.2
Exercises · Barentsz Seasurge	3	21	1	12	2.5× / 1.2
Nav aids · Great Australian Bightsurge	3	20.5	1	14	5.0× / 0.6
Quakes · North Atlantic Oceansurge	3	9	0	—	2.5× / 1.2
Derelicts · North Atlantic Ocean	3	7.3	0	—	0.9× / 3.2
Nav aids · Caribbean Sea	2	305.3	10	170	1.4× / 1.4
Wrecks · Persian Gulflong running	2	268.7	9	637	10× / 0.2
Nav aids · South Pacific Oceanlong running	2	176.5	7	877	0.7× / 2.8
Surveys · Mediterranean Sea - Eastern Basin	2	143.7	4	134	0.5× / 4.4
Nav aids · Persian Gulf	2	100	3	350	10× / 0.2
Wrecks · South Atlantic Ocean	2	86.6	3	247	3.3× / 0.6
Nav aids · Gulf of Mexico	2	64.1	2	116	0.6× / 3.2
Surveys · Bay of Bengal	2	51.8	0	—	0.8× / 2.6
Surveys · Irish Sea and St. George's Channel	2	32.3	2	48	10× / 0.2
Spills · Bering Sea	2	31	0	—	3.3× / 0.6
Other · North Atlantic Ocean	2	27.8	2	16	0.3× / 7.6
Incidents · Bay of Bengal	2	24.9	2	43	3.3× / 0.6
Missiles · South Pacific Ocean	2	20.3	0	—	1.0× / 2
Incidents · Mediterranean Sea - Western Basin	2	20.2	1	25	3.3× / 0.6
Incidents · Gulf of Thailand	2	17.5	0	—	1.4× / 1.4
Incidents · Indian Ocean	2	14.4	0	—	0.4× / 5.4
Piracy · Gulf of Guinea	2	14	0	—	0.3× / 6
Cable ops · Mediterranean Sea - Eastern Basin	2	12.7	1	119	1.0× / 2
Surveys · North Pacific Ocean	2	10.9	1	26	10× / 0.2
Nav aids · Celtic Sea	2	10.5	0	—	1.4× / 1.4
Other · Coral Sea	2	9	1	8	1.7× / 1.2
Quakes · Indian Ocean	2	6.5	0	—	0.8× / 2.6
Icebergs · Barentsz Sea	2	6	0	—	3.3× / 0.6
Derelicts · North Pacific Ocean	2	6	0	—	1.7× / 1.2
Quakes · Philippine Sea	2	6	0	—	2.0× / 1
Quakes · South Atlantic Ocean	2	6	0	—	1.4× / 1.4
Quakes · Southern Ocean	2	6	0	—	10× / 0.2
Debris · Gulf of Mexico	2	5.3	0	—	5.0× / 0.4
Other · North Pacific Ocean	2	3.8	0	—	1.3× / 1.6
Other · Irish Sea and St. George's Channel	2	2.5	0	—	10× / 0.2
Nav aids · Mediterranean Sea - Western Basin	1	115	4	304	0.5× / 2
Nav aids · Andaman or Burma Sea	1	78.1	3	86	1.0× / 1
Other · Persian Gulf	1	71.4	3	268	5.0× / 0.2
Surveys · Indian Ocean	1	71	2	86	0.6× / 1.8
Nav aids · Laccadive Sea	1	46.5	2	33	1.3× / 0.8
Other · Gulf of Mexico	1	40.3	2	79	5.0× / 0.2
Surveys · South Pacific Oceanlong running	1	39.1	2	546	0.8× / 1.2
Nav aids · Bay of Bengal	1	32.6	2	294	0.8× / 1.2
Incidents · Java Sealong running	1	31.2	1	387	0.7× / 1.4
Surveys · Celtic Sea	1	31	1	40	1.7× / 0.6
Nav aids · Norwegian Sea	1	31	1	61	new / 0
Structures · Arabian Sea	1	30.4	1	30	5.0× / 0.2
Exercises · Laccadive Sea	1	30.2	1	33	0.4× / 2.8
Surveys · Great Australian Bight	1	26.8	1	26	0.7× / 1.4
Surveys · Caribbean Sea	1	21.9	1	35	0.7× / 1.4
Wrecks · Indian Ocean	1	17.6	0	—	2.5× / 0.4
Spills · The Coastal Waters of Southeast Alaska and British Columbia	1	17	1	42	0.7× / 1.4
Cable ops · Sea of Marmara	1	14.5	0	—	5.0× / 0.2
Incidents · Black Sea	1	13.7	0	—	5.0× / 0.2
Other · Sea of Okhotsk	1	10.6	1	10	new / 0
Cable ops · Singapore Strait	1	9.5	0	—	1.7× / 0.6
Cable ops · Philippine Sea	1	9	0	—	1.3× / 0.8
Surveys · Japan Sea	1	8.6	1	8	new / 0
Derelicts · Red Sea	1	8.5	1	8	new / 0
Surveys · Philippine Sea	1	8.4	0	—	5.0× / 0.2
Missiles · Baffin Bay	1	8.3	0	—	new / 0
Incidents · Bismarck Sea	1	8.2	0	—	0.6× / 1.6
Wrecks · Caribbean Sea	1	8.2	1	8	1.3× / 0.8
Cable ops · Strait of Gibraltar	1	6.4	0	—	5.0× / 0.2
Exercises · South China Sea	1	6.2	1	6	0.5× / 2
Quakes · Coral Sea	1	6	0	—	0.8× / 1.2
Nav aids · Indian Ocean	1	5.4	1	5	0.7× / 1.4
Missiles · North Pacific Ocean	1	5	0	—	0.1× / 6.8
Missiles · Arctic Ocean	1	4.8	0	—	0.8× / 1.2
Incidents · Ceram Sea	1	4.7	0	—	new / 0
Nav aids · Irish Sea and St. George's Channel	1	4.6	0	—	1.3× / 0.8
Ordnance · North Pacific Ocean	1	4	0	—	5.0× / 0.2
Missiles · Bay of Bengal	1	3.2	0	—	1.7× / 0.6
Quakes · Adriatic Sea	1	3	0	—	new / 0
Quakes · Aegean Sea	1	3	0	—	new / 0
Debris · Arafura Sea	1	3	0	—	new / 0
Quakes · Arafura Sea	1	3	0	—	new / 0
Debris · Bay of Bengal	1	3	0	—	new / 0
Quakes · Eastern China Sea	1	3	0	—	5.0× / 0.2
Derelicts · Indian Ocean	1	3	0	—	0.7× / 1.4
Derelicts · Laccadive Sea	1	3	0	—	0.7× / 1.4
Derelicts · Mediterranean Sea - Western Basin	1	3	0	—	5.0× / 0.2
Quakes · Mediterranean Sea - Western Basin	1	3	0	—	new / 0
Containers · North Atlantic Ocean	1	3	0	—	1.3× / 0.8
Quakes · Solomon Sea	1	3	0	—	0.4× / 2.8
Derelicts · South Pacific Ocean	1	3	0	—	0.6× / 1.6
Derelicts · Tasman Sea	1	3	0	—	1.3× / 0.8
Debris · Timor Sea	1	3	0	—	2.5× / 0.4
Derelicts · Mediterranean Sea - Eastern Basin	1	2.7	1	33	new / 0
Debris · Indian Ocean	1	2.6	1	2	0.6× / 1.8
Other · Gulf of Alaska	1	2.4	0	—	1.7× / 0.6
Incidents · Persian Gulf	1	2.3	0	—	new / 0
Derelicts · Persian Gulf	1	1	0	—	2.5× / 0.4
Derelicts · Mozambique Channel	1	0.8	1	0	1.7× / 0.6
Derelicts · South China Sea	1	0.7	0	—	0.7× / 1.4
Wrecks · South Pacific Ocean	1	0.6	1	0	5.0× / 0.2
Structures · South Atlantic Ocean	1	0.5	0	—	5.0× / 0.2
Incidents · Malacca Strait	1	0.4	0	—	1.3× / 0.8
Incidents · Arafura Sea	1	0.2	0	—	1.3× / 0.8
Incidents · Eastern China Sea	1	0.1	0	—	0.6× / 1.8
Debris · Mediterranean Sea - Eastern Basin	1	0.1	1	0	5.0× / 0.2
Incidents · Coral Sea	1	0	0	—	0.2× / 4.2
Wrecks · South China Sealong running	0	279	9	773	0.0× / 1.2
Wrecks · North Atlantic Oceanlong running	0	124	4	800	— / 0
Exercises · Ionian Sea	0	100.5	3	78	0.0× / 0.2
Derelicts · Arabian Sealong running	0	62	2	432	0.0× / 0.8
Nav aids · Arabian Sea	0	62	2	86	0.0× / 0.6
Wrecks · Arabian Sealong running	0	62	2	554	0.0× / 0.2
Surveys · Arctic Ocean	0	62	2	163	— / 0
Wrecks · Inner Seas off the West Coast of Scotland	0	62	2	173	0.0× / 0.4
Nav aids · Mozambique Channel	0	62	2	168	0.0× / 0.6
Wrecks · North Pacific Oceanlong running	0	62	2	727	— / 0
Ordnance · North Sealong running	0	62	2	534	0.0× / 1
Volcanic · Philippine Sea	0	62	2	103	0.0× / 0.2
Restricted · South Atlantic Oceanlong running	0	62	2	454	0.0× / 1
Surveys · Barentsz Sea	0	54.3	1	75	0.0× / 0.4
Cable ops · Persian Gulf	0	35.7	1	129	0.0× / 0.4
Incidents · Caribbean Sea	0	34.8	0	—	0.0× / 5.2
Cable ops · Caribbean Sea	0	34.4	1	124	0.0× / 0.4
Incidents · Mediterranean Sea - Eastern Basin	0	31.1	0	—	0.0× / 14.6
Cable ops · Aegean Sea	0	31	1	107	0.0× / 0.2
Missiles · Aegean Sea	0	31	1	78	0.0× / 0.2
Nav aids · Alboran Sea	0	31	1	188	0.0× / 0.4
Nav aids · Arafura Sea	0	31	1	35	0.0× / 1
Other · Bering Sea	0	31	1	36	0.0× / 0.6
Surveys · Bering Sea	0	31	1	161	— / 0
Cable ops · Black Sea	0	31	1	64	0.0× / 0.4
Mines · English Channel	0	31	1	33	— / 0
Wrecks · English Channel	0	31	1	82	0.0× / 1
Nav aids · Gulf of California	0	31	1	43	0.0× / 0.2
Nav aids · Gulf of Thailandlong running	0	31	1	531	— / 0
Wrecks · Japan Sea	0	31	1	69	— / 0
Surveys · Ligurian Sea	0	31	1	31	— / 0
Nav aids · Mediterranean Sea - Eastern Basin	0	31	1	237	— / 0
Other · Mediterranean Sea - Eastern Basin	0	31	1	188	0.0× / 0.6
Volcanic · Mozambique Channellong running	0	31	1	545	— / 0
Wrecks · Mozambique Channel	0	31	1	168	— / 0
Mines · Persian Gulf	0	31	1	87	— / 0
Restricted · Persian Gulflong running	0	31	1	714	0.0× / 0.2
Wrecks · Red Sealong running	0	31	1	473	— / 0
Cable ops · South China Sea	0	31	1	42	0.0× / 1.4
Structures · South China Sealong running	0	31	1	492	— / 0
Surveys · South China Sealong running	0	31	1	566	0.0× / 0.8
Wrecks · Southern Ocean	0	31	1	35	— / 0
Nav aids · Tasman Sea	0	31	1	33	0.0× / 1.8
Surveys · Tyrrhenian Sea	0	31	1	59	— / 0

Cite: seahazards.com Sea Ledger, 2021-03, 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.