Sea Ledger, September 2021

2021-09-01 to 2021-09-30 · archive

issued: 615
warning-days in force: 11,241
in force at month end: 372
sea × type cells: 249

baseline: same month, previous 5 years (2020-09, 2019-09, 2018-09, 2017-09, 2016-09)

By type

type	issued	warning-days	in force at end
Exercises	116	1,517.6	47
Incidents	92	687.9	28
Icebergs	74	90.8	3
Surveys	62	2,219.8	71
Missiles	56	308.2	14
Nav aids	49	2,971.6	98
Derelicts	35	189.7	5
Quakes	33	100.3	1
Other	28	472.5	19
Cable ops	25	508	18
Towing	16	15.3	1
Wrecks	6	1,460.7	47
Spills	6	147	1
Storms	5	18.5	0
Debris	4	9.9	1
Ordnance	3	104.2	4
Volcanic	2	219.5	8
Piracy	2	14	0
Containers	1	3	0
Structures	0	60	2
Restricted	0	92.5	3
Mines	0	30	1

By sea and type · 200 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Icebergs · Southern Oceansurge	34	34.6	0	—	2.0× / 16.8
Exercises · North Pacific Ocean	29	297.7	9	140	1.3× / 23
Surveys · South Atlantic Oceansurge	22	176.5	3	116	2.0× / 11
Icebergs · Labrador Sea	22	25.6	2	31	0.9× / 25.4
Incidents · South China Sealong running	20	126	5	542	0.8× / 25
Exercises · South Pacific Oceansurge	19	106.9	3	35	2.6× / 7.4
Missiles · Barentsz Seasurge	16	78.1	4	31	2.2× / 7.4
Towing · North Pacific Oceannew	16	15.3	1	30	new / 0
Incidents · North Pacific Ocean	13	125.2	3	44	0.6× / 20.4
Incidents · Indian Oceansurge	10	35.8	3	32	2.2× / 4.6
Quakes · North Pacific Ocean	10	27	0	—	1.4× / 7
Derelicts · Timor Seasurge	10	15.4	0	—	50× / 0.2
Exercises · South Atlantic Ocean	9	101.3	9	36	0.7× / 12.4
Missiles · North Pacific Ocean	9	74.7	2	107	0.9× / 10
Exercises · North Atlantic Ocean	9	52.8	2	35	0.9× / 9.8
Icebergs · Davis Straitnew	9	9.5	0	—	new / 0
Exercises · Black Sea	8	265.2	5	36	0.5× / 17
Incidents · Laccadive Seasurge	8	91.9	4	45	3.6× / 2.2
Exercises · Arabian Sea	8	91.5	1	34	1.0× / 8.2
Quakes · South Atlantic Oceansurge	8	27.6	0	—	4.4× / 1.8
Cable ops · North Atlantic Ocean	7	147.9	5	89	1.1× / 6.6
Quakes · South Pacific Ocean	7	23.1	0	—	0.5× / 13.8
Nav aids · North Pacific Oceanlong running	6	227.9	8	790	1.3× / 4.6
Exercises · Bay of Bengal	6	62.7	0	—	0.6× / 10.8
Incidents · South Pacific Ocean	6	60.7	1	40	1.3× / 4.8
Incidents · South Atlantic Ocean	6	46.2	2	42	0.9× / 6.4
Missiles · North Atlantic Ocean	6	16.4	1	23	0.9× / 6.4
Derelicts · North Atlantic Ocean	6	15.1	0	—	1.9× / 3.2
Derelicts · Indian Ocean	6	14.1	0	—	1.6× / 3.8
Surveys · North Atlantic Ocean	5	517	18	273	1.0× / 5
Nav aids · South Pacific Oceanlong running	5	262.3	8	1,060	1.5× / 3.4
Nav aids · North Sea	5	133	4	240	0.7× / 7.2
Surveys · Caribbean Seasurge	5	90	3	41	2.8× / 1.8
Nav aids · English Channel	5	66.7	1	71	1.6× / 3.2
Other · North Seasurge	5	31.3	0	—	8.3× / 0.6
Incidents · Arabian Sea	5	29	3	36	1.6× / 3.2
Storms · Gulf of Mexico	5	18.5	0	—	1.0× / 4.8
Nav aids · North Atlantic Oceanlong running	4	310.9	12	782	0.8× / 5.2
Surveys · Persian Gulf	4	125.7	3	255	1.1× / 3.6
Surveys · Indian Oceansurge	4	72.3	3	226	5.0× / 0.8
Missiles · Laptev Seasurge	4	32	0	—	4.0× / 1
Other · Gulf of Mexicosurge	4	30.6	2	31	10× / 0.4
Other · English Channelsurge	4	24.8	2	17	6.7× / 0.6
Missiles · Black Sea	4	18.1	1	24	0.6× / 7
Missiles · Japan Seasurge	4	17.1	3	28	20× / 0.2
Exercises · Mediterranean Sea - Western Basinsurge	4	13.5	1	17	2.2× / 1.8
Exercises · Caribbean Seasurge	4	13	0	—	4.0× / 1
Icebergs · South Atlantic Ocean	4	4	0	—	0.1× / 28.6
Incidents · Coral Sea	4	3.1	0	—	0.7× / 5.8
Nav aids · South Atlantic Ocean	3	169.4	7	174	0.4× / 8.2
Wrecks · The Northwestern Passages	3	117.9	4	30	1.9× / 1.6
Nav aids · Coral Sea	3	66	2	105	0.7× / 4.2
Other · North Pacific Ocean	3	50.2	1	181	0.6× / 5.2
Cable ops · North Pacific Oceansurge	3	44.8	2	196	3.8× / 0.8
Exercises · Laccadive Sea	3	36.2	1	30	1.3× / 2.4
Incidents · Bay of Bengalsurge	3	24.6	2	23	3.0× / 1
Cable ops · Hudson Baynew	3	23.8	1	36	new / 0
Surveys · Arabian Sea	3	14.8	2	13	1.5× / 2
Ordnance · North Pacific Oceansurge	3	14.2	1	34	15× / 0.2
Other · North Atlantic Ocean	3	11.4	2	27	1.7× / 1.8
Nav aids · Inner Seas off the West Coast of Scotland	3	10.8	0	—	1.1× / 2.6
Derelicts · South Pacific Oceansurge	3	6.9	1	29	3.0× / 1
Missiles · South Pacific Ocean	3	5.9	0	—	1.3× / 2.4
Exercises · Philippine Sea	3	4.1	2	19	0.4× / 7.4
Missiles · Great Australian Bightnew	3	3.7	0	—	new / 0
Nav aids · Arabian Sea	2	144	5	121	1.4× / 1.4
Exercises · Mediterranean Sea - Eastern Basin	2	87.8	2	104	0.1× / 18
Surveys · South Pacific Oceanlong running	2	64.9	3	729	10× / 0.2
Cable ops · Indian Ocean	2	46	2	104	2.5× / 0.8
Spills · North Pacific Ocean	2	46	0	—	1.1× / 1.8
Spills · North Atlantic Ocean	2	38	0	—	0.7× / 2.8
Cable ops · Caribbean Sea	2	37.2	1	31	3.3× / 0.6
Incidents · Mediterranean Sea - Western Basin	2	36.2	0	—	2.0× / 1
Cable ops · North Sea	2	27.1	1	27	0.8× / 2.6
Surveys · Mediterranean Sea - Western Basin	2	25.7	1	35	5.0× / 0.4
Cable ops · Strait of Gibraltar	2	23.6	2	13	3.3× / 0.6
Surveys · The Northwestern Passages	2	18.1	1	15	3.3× / 0.6
Derelicts · Bay of Bengal	2	16.5	1	16	0.6× / 3.2
Exercises · Japan Sea	2	14.8	0	—	1.7× / 1.2
Surveys · Ligurian Seanew	2	13.5	0	—	new / 0
Derelicts · North Pacific Ocean	2	13	0	—	1.1× / 1.8
Incidents · Philippine Sea	2	10.9	0	—	0.5× / 4
Volcanic · North Atlantic Oceannew	2	9.5	1	9	new / 0
Exercises · Laptev Sea	2	9.2	0	—	10× / 0.2
Nav aids · Beaufort Sea	2	8.5	1	13	3.3× / 0.6
Exercises · Kara Sea	2	7.2	1	7	10× / 0.2
Other · South Atlantic Ocean	2	7	0	—	2.5× / 0.8
Incidents · Bismarck Sea	2	6.4	1	12	1.4× / 1.4
Icebergs · Barentsz Seanew	2	6	0	—	new / 0
Quakes · Philippine Sea	2	6	0	—	0.6× / 3.4
Icebergs · Indian Oceannew	2	5.5	1	21	new / 0
Incidents · North Atlantic Ocean	2	5.5	1	16	0.2× / 10.8
Wrecks · Timor Seanew	2	4.1	0	—	new / 0
Other · Bering Sea	2	2.8	1	21	3.3× / 0.6
Incidents · Timor Sea	2	0.5	0	—	2.5× / 0.8
Nav aids · Caribbean Sea	1	310.5	9	353	0.2× / 4.4
Nav aids · Gulf of Mexico	1	245.2	8	299	0.3× / 3.8
Surveys · Sea of Okhotsk	1	104	4	104	0.6× / 1.6
Surveys · Black Sea	1	77	2	204	0.5× / 2.2
Nav aids · Laccadive Sea	1	60	2	70	2.5× / 0.4
Nav aids · Bass Strait	1	56.6	0	—	5.0× / 0.2
Surveys · Hudson Bay	1	55.3	2	43	new / 0
Other · Arafura Sea	1	47.9	2	176	new / 0
Surveys · Bay of Biscay	1	37.1	1	87	2.5× / 0.4
Nav aids · Andaman or Burma Sea	1	36.2	2	269	1.7× / 0.6
Derelicts · Arabian Sea	1	33	1	104	1.0× / 1
Surveys · Bay of Bengal	1	31.1	1	35	0.3× / 3.4
Nav aids · Celtic Sea	1	30	1	118	0.6× / 1.8
Cable ops · Norwegian Sea	1	27.2	1	27	5.0× / 0.2
Cable ops · Celtic Sea	1	24.8	0	—	1.0× / 1
Nav aids · Irish Sea and St. George's Channel	1	24.8	1	24	0.4× / 2.8
Spills · Gulf of Mexico	1	23	0	—	0.1× / 6.8
Other · Arabian Sea	1	21.2	1	21	new / 0
Exercises · Andaman or Burma Sea	1	18	0	—	0.5× / 2.2
Spills · The Coastal Waters of Southeast Alaska and British Columbia	1	18	1	36	2.5× / 0.4
Cable ops · English Channel	1	15.5	1	15	5.0× / 0.2
Cable ops · Mediterranean Sea - Western Basin	1	15	0	—	new / 0
Other · South Pacific Ocean	1	14.1	1	14	2.5× / 0.4
Incidents · Caribbean Sea	1	14	1	14	0.2× / 5.8
Surveys · Laccadive Sea	1	13.5	1	13	new / 0
Surveys · Balearic (Iberian Sea)	1	13.2	1	13	2.5× / 0.4
Other · Hudson Bay	1	10.3	1	10	2.5× / 0.4
Nav aids · The Northwestern Passages	1	9.7	1	9	0.8× / 1.2
Wrecks · Kara Sea	1	9.6	0	—	2.5× / 0.4
Other · Labrador Sea	1	8.7	0	—	new / 0
Missiles · Arctic Ocean	1	8.3	0	—	1.3× / 0.8
Surveys · Hudson Strait	1	7.3	0	—	new / 0
Surveys · Mozambique Channel	1	7.1	1	7	5.0× / 0.2
Piracy · Gulf of Guinea	1	7	0	—	1.0× / 1
Piracy · Red Sea	1	7	0	—	5.0× / 0.2
Incidents · Banda Sea	1	6.7	0	—	1.3× / 0.8
Derelicts · Banda Sea	1	6	0	—	new / 0
Exercises · Coral Sea	1	5.5	0	—	1.3× / 0.8
Missiles · Philippine Sea	1	5	1	4	new / 0
Missiles · South Atlantic Ocean	1	4.8	0	—	5.0× / 0.2
Missiles · Indian Ocean	1	4.7	0	—	0.3× / 3.6
Exercises · Alboran Sea	1	4	1	3	new / 0
Missiles · South China Sea	1	3.9	0	—	5.0× / 0.2
Exercises · Norwegian Sea	1	3.7	0	—	2.5× / 0.4
Missiles · Norwegian Sea	1	3.6	1	3	5.0× / 0.2
Exercises · Ligurian Sea	1	3.4	0	—	new / 0
Nav aids · Barentsz Sea	1	3.2	1	3	new / 0
Quakes · Aegean Sea	1	3	0	—	new / 0
Derelicts · Arafura Sea	1	3	0	—	new / 0
Incidents · Barentsz Sea	1	3	0	—	new / 0
Derelicts · Coral Sea	1	3	0	—	1.3× / 0.8
Quakes · Coral Sea	1	3	0	—	0.6× / 1.8
Derelicts · English Channel	1	3	0	—	new / 0
Quakes · Indian Ocean	1	3	0	—	0.5× / 2.2
Icebergs · Laptev Sea	1	3	0	—	0.6× / 1.8
Debris · North Atlantic Ocean	1	3	0	—	0.5× / 2.2
Containers · North Pacific Ocean	1	3	0	—	new / 0
Debris · North Pacific Ocean	1	3	0	—	new / 0
Quakes · Sea of Okhotsk	1	3	0	—	5.0× / 0.2
Quakes · Southern Ocean	1	3	0	—	new / 0
Debris · Indian Ocean	1	2	0	—	1.3× / 0.8
Missiles · Laccadive Sea	1	1.9	0	—	0.6× / 1.6
Debris · South Pacific Ocean	1	1.9	1	1	2.5× / 0.4
Quakes · Japan Sea	1	1.6	1	1	new / 0
Incidents · Norwegian Sea	1	0.8	0	—	2.5× / 0.4
Incidents · Tasman Sea	1	0.8	0	—	1.0× / 1
Derelicts · Solomon Sea	1	0.7	0	—	new / 0
Incidents · Arafura Sea	1	0.4	0	—	2.5× / 0.4
Exercises · North Sea	1	0.4	0	—	new / 0
Nav aids · Adriatic Sea	1	0.2	0	—	new / 0
Incidents · Hudson Bay	1	0.2	0	—	2.5× / 0.4
Surveys · North Pacific Ocean	1	0.2	1	0	5.0× / 0.2
Nav aids · Bering Sea	1	0.1	1	0	new / 0
Surveys · Tasman Sea	1	0.1	0	—	2.5× / 0.4
Wrecks · North Atlantic Oceanlong running	0	300	10	983	0.0× / 0.4
Wrecks · South China Sealong running	0	234.5	7	956	0.0× / 1
Exercises · Aegean Sea	0	180	6	261	0.0× / 10.2
Nav aids · Mediterranean Sea - Western Basinlong running	0	150	5	447	0.0× / 0.6
Volcanic · Philippine Sea	0	150	5	286	0.0× / 0.4
Nav aids · Bay of Bengallong running	0	142.5	4	477	0.0× / 1.6
Wrecks · Arabian Sealong running	0	120	4	737	0.0× / 1.8
Surveys · Kara Sea	0	120	4	78	0.0× / 2
Wrecks · South Atlantic Ocean	0	120	4	255	0.0× / 0.8
Surveys · Arctic Ocean	0	90	3	346	0.0× / 1.2
Exercises · Ionian Sea	0	90	3	261	— / 0
Nav aids · Mozambique Channel	0	90	3	351	0.0× / 0.2
Wrecks · North Pacific Oceanlong running	0	90	3	910	0.0× / 0.2
Ordnance · North Sealong running	0	90	3	717	0.0× / 1
Other · Persian Gulflong running	0	90	3	451	0.0× / 0.4
Wrecks · Persian Gulf	0	90	3	328	— / 0
Surveys · North Sea	0	87.4	2	101	0.0× / 4
Nav aids · Indian Ocean	0	75	2	173	0.0× / 2.8
Surveys · Barentsz Sea	0	60	2	163	0.0× / 1.6
Wrecks · Bay of Bengal	0	60	2	98	— / 0
Wrecks · English Channel	0	60	2	265	0.0× / 0.2
Wrecks · Inner Seas off the West Coast of Scotland	0	60	2	356	0.0× / 0.6
Wrecks · Laccadive Sea	0	60	2	134	0.0× / 0.2
Nav aids · Mediterranean Sea - Eastern Basin	0	60	2	143	0.0× / 0.2
Restricted · South Atlantic Oceanlong running	0	60	2	637	0.0× / 1.2
Structures · South Atlantic Ocean	0	60	2	119	0.0× / 1
Nav aids · Tasman Sea	0	60	2	216	0.0× / 0.6
Surveys · Mediterranean Sea - Eastern Basin	0	58.8	1	57	0.0× / 7
Surveys · Gulf of Guinea	0	53.1	1	117	0.0× / 0.2
Surveys · Norwegian Sea	0	46.4	1	110	0.0× / 1.2
Surveys · Gulf of Mexico	0	31	1	61	— / 0

Cite: seahazards.com Sea Ledger, 2021-09, 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.