Sea Ledger, October 2023

2023-10-01 to 2023-10-31 · archive

issued: 725
warning-days in force: 14,570
in force at month end: 496
sea × type cells: 234

baseline: same month, previous 5 years (2022-10, 2021-10, 2020-10, 2019-10, 2018-10)

By type

type	issued	warning-days	in force at end
Exercises	162	1,392.4	43
Incidents	103	1,199.9	42
Icebergs	86	94.4	4
Nav aids	74	4,858.5	160
Surveys	69	2,468.3	87
Missiles	59	623.3	20
Quakes	50	148.6	3
Cable ops	27	640.9	25
Derelicts	18	123.7	7
Other	17	598.4	19
Towing	17	17.7	1
Spills	14	193	7
Wrecks	13	1,417.7	52
Storms	6	9	0
Debris	4	71.9	2
Volcanic	3	298	10
Mines	2	101	4
Containers	1	3	0
Structures	0	124	4
Restricted	0	62	2
War risk	0	31	1
Ordnance	0	93	3

By sea and type · 200 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Icebergs · Labrador Sea	32	36.6	2	32	1.1× / 28.8
Exercises · North Pacific Ocean	29	306.7	14	65	1.1× / 26
Icebergs · South Atlantic Ocean	29	28.9	1	31	1.5× / 19.2
Icebergs · Southern Ocean	23	22.9	1	31	0.6× / 38.6
Incidents · North Atlantic Oceansurge	20	248.2	13	37	2.6× / 7.8
Surveys · South Atlantic Ocean	20	230.1	8	159	1.1× / 17.8
Incidents · South China Sea	20	179.3	7	34	0.7× / 28.4
Missiles · North Atlantic Ocean	19	84.9	3	31	2.0× / 9.6
Exercises · South Pacific Ocean	18	62.7	2	34	1.4× / 12.6
Towing · North Pacific Ocean	17	17.7	1	17	1.9× / 8.8
Incidents · North Pacific Ocean	15	184.1	7	34	0.8× / 17.6
Exercises · Bay of Bengal	15	127	3	34	1.0× / 14.8
Exercises · Celtic Seasurge	15	18.6	0	—	4.0× / 3.8
Missiles · Indian Oceansurge	14	174.1	4	40	4.4× / 3.2
Exercises · North Atlantic Ocean	14	77.2	4	65	1.2× / 11.8
Exercises · Arabian Sea	13	89.6	4	34	0.9× / 15
Quakes · Philippine Seasurge	13	37.6	0	—	4.6× / 2.8
Quakes · South Pacific Ocean	13	35.1	2	32	1.1× / 11.6
Nav aids · North Atlantic Oceanlong running	12	331	11	929	1.6× / 7.6
Missiles · Barentsz Sea	11	87.5	2	36	1.3× / 8.8
Exercises · South Atlantic Ocean	11	46.5	1	36	1.1× / 10
Surveys · South Pacific Oceansurge	9	178.5	4	224	5.6× / 1.6
Surveys · Arabian Sea	9	178.2	8	55	1.1× / 8.2
Nav aids · North Pacific Oceanlong running	8	231.9	7	573	1.7× / 4.6
Spills · Gulf of Mexico	8	96	3	30	1.5× / 5.4
Exercises · Laccadive Seasurge	8	49.2	2	32	2.7× / 3
Exercises · Andaman or Burma Seasurge	8	46.3	0	—	2.5× / 3.2
Exercises · Bay of Biscaysurge	8	19	0	—	5.7× / 1.4
Nav aids · South Atlantic Oceanlong running	7	1,327.5	41	445	1.3× / 5.6
Other · North Pacific Ocean	7	47.2	2	31	1.0× / 6.8
Nav aids · South Pacific Oceanlong running	6	384.8	13	586	1.6× / 3.8
Cable ops · North Atlantic Ocean	6	159.5	5	144	0.6× / 10.2
Surveys · Indian Ocean	6	147.2	7	249	1.7× / 3.6
Incidents · Coral Seasurge	6	20.6	1	26	2.5× / 2.4
Quakes · Bismarck Seasurge	6	18	0	—	30× / 0.2
Derelicts · North Atlantic Ocean	6	16.2	2	31	1.1× / 5.6
Surveys · North Atlantic Ocean	5	323.5	11	303	0.4× / 11.8
Nav aids · Gulf of Mexicosurgelong running	5	255.6	8	942	3.1× / 1.6
Missiles · North Pacific Oceansurge	5	72.6	3	245	2.8× / 1.8
Incidents · South Pacific Ocean	5	58.7	1	45	0.9× / 5.4
Exercises · Gulf of Mexico	5	46.3	0	—	1.6× / 3.2
Cable ops · Caribbean Seasurge	5	15.9	2	14	25× / 0.2
Nav aids · Coral Sea	4	140.5	6	191	1.8× / 2.2
Exercises · Black Sealong running	4	104.1	3	587	0.2× / 22.2
Incidents · South Atlantic Ocean	4	87.8	1	44	1.2× / 3.4
Exercises · Japan Sea	4	67.7	1	34	1.3× / 3
Nav aids · North Sea	4	65.7	2	130	0.7× / 6.2
Incidents · Gulf of Mexicosurge	4	63.8	4	42	2.9× / 1.4
Nav aids · Inner Seas off the West Coast of Scotland	4	63.2	3	33	0.8× / 4.8
Wrecks · North Atlantic Oceansurge	4	42.7	4	13	20× / 0.2
Incidents · Indian Ocean	4	29.7	1	30	0.7× / 6
Exercises · Indian Ocean	4	22.7	0	—	1.5× / 2.6
Surveys · Persian Gulflong running	3	178	7	537	0.4× / 7.2
Cable ops · Arabian Sea	3	92.5	3	47	1.3× / 2.4
Incidents · Caribbean Sea	3	70.6	0	—	1.7× / 1.8
Exercises · Caribbean Sea	3	46.9	1	39	1.3× / 2.4
Incidents · Mediterranean Sea - Eastern Basin	3	42.7	1	29	0.9× / 3.2
Spills · The Coastal Waters of Southeast Alaska and British Columbiasurge	3	25	2	21	2.5× / 1.2
Incidents · Bay of Bengal	3	23.8	2	19	1.7× / 1.8
Nav aids · Davis Strait	3	17.8	0	—	1.3× / 2.4
Quakes · North Pacific Ocean	3	9.7	0	—	0.5× / 6
Quakes · Bering Seasurge	3	9	0	—	15× / 0.2
Nav aids · Gulf of Alaskasurge	3	7.9	0	—	2.5× / 1.2
Derelicts · South Pacific Ocean	3	6	2	3	1.4× / 2.2
Storms · Caribbean Seanew	3	4.7	0	—	new / 0
Storms · Philippine Sea	3	4.3	0	—	1.7× / 1.8
Incidents · Bass Straitsurge	3	0.3	0	—	15× / 0.2
Nav aids · Caribbean Sealong running	2	859.3	28	987	0.7× / 2.8
Volcanic · Philippine Sealong running	2	282.2	9	1,047	2.0× / 1
Surveys · The Northwestern Passageslong running	2	213	7	438	3.3× / 0.6
Cable ops · Persian Gulf	2	177.2	6	223	3.3× / 0.6
Mines · Black Seanewlong running	2	101	4	614	new / 0
Surveys · Arctic Oceanlong running	2	96.6	3	415	3.3× / 0.6
Nav aids · Celtic Sea	2	85.9	4	50	2.0× / 1
Nav aids · Indian Ocean	2	83.9	3	69	1.0× / 2
Surveys · Bay of Bengal	2	76.3	3	40	1.3× / 1.6
Nav aids · The Northwestern Passages	2	74	2	99	1.3× / 1.6
Surveys · Bass Strait	2	69.6	2	208	5.0× / 0.4
Surveys · Barentsz Sea	2	59	3	33	3.3× / 0.6
Incidents · Ionian Sea	2	49.3	0	—	5.0× / 0.4
Wrecks · South Pacific Ocean	2	43.7	2	211	3.3× / 0.6
Cable ops · North Pacific Ocean	2	36.7	2	102	1.4× / 1.4
Nav aids · Arafura Sea	2	33.5	2	25	3.3× / 0.6
Wrecks · Kara Sea	2	28.3	2	14	10× / 0.2
Cable ops · South Pacific Ocean	2	21	1	21	10× / 0.2
Derelicts · Indian Ocean	2	19.7	1	22	0.6× / 3.6
Missiles · Bay of Bengal	2	10.3	0	—	2.5× / 0.8
Quakes · Indian Ocean	2	8	0	—	0.8× / 2.4
Nav aids · English Channel	2	7	0	—	0.8× / 2.6
Exercises · Philippine Sea	2	7	0	—	0.8× / 2.4
Other · Barentsz Sea	2	6.6	0	—	10× / 0.2
Quakes · Coral Sea	2	6.4	1	33	1.7× / 1.2
Quakes · Banda Sea	2	6	0	—	3.3× / 0.6
Quakes · Southern Ocean	2	6	0	—	5.0× / 0.4
Missiles · Philippine Sea	2	2.1	2	1	1.4× / 1.4
Wrecks · The Northwestern Passageslong running	1	159.9	6	789	5.0× / 0.2
Wrecks · Caribbean Sea	1	152.8	5	233	1.7× / 0.6
Surveys · Gulf of Mexico	1	124	4	184	2.5× / 0.4
Wrecks · Hudson Baylong running	1	107.3	4	368	2.5× / 0.4
Missiles · South Pacific Ocean	1	98	3	42	0.2× / 4.4
Nav aids · Persian Gulflong running	1	93	3	525	5.0× / 0.2
Other · South Atlantic Ocean	1	70.5	2	185	1.3× / 0.8
Surveys · Caribbean Sealong running	1	69.4	2	366	0.5× / 2
Nav aids · Hudson Baylong running	1	57.2	2	412	1.7× / 0.6
Cable ops · South Atlantic Ocean	1	48.3	1	130	5.0× / 0.2
Nav aids · Hudson Strait	1	45.1	2	109	new / 0
Cable ops · Malacca Strait	1	40.5	1	32	new / 0
Missiles · Arctic Ocean	1	39.5	1	31	1.7× / 0.6
Surveys · Black Sea	1	38.6	2	271	0.6× / 1.6
Other · Bay of Biscay	1	36.7	2	286	5.0× / 0.2
Wrecks · Bay of Bengal	1	35.8	2	97	5.0× / 0.2
Spills · North Atlantic Oceanlong running	1	35	2	467	0.4× / 2.4
Debris · Bay of Biscaylong running	1	34	1	419	new / 0
Derelicts · Laccadive Sea	1	34	1	98	0.7× / 1.4
Derelicts · South Atlantic Ocean	1	34	1	227	0.8× / 1.2
Nav aids · Arctic Oceanlong running	1	31	1	405	new / 0
Wrecks · Indian Ocean	1	29.9	1	29	new / 0
Cable ops · Japan Sea	1	24.6	1	24	new / 0
Spills · North Pacific Ocean	1	23	0	—	0.4× / 2.4
Surveys · Mediterranean Sea - Eastern Basin	1	22.5	1	60	0.2× / 6
Nav aids · Bass Strait	1	20.7	1	20	2.5× / 0.4
Other · North Sea	1	18.4	1	18	5.0× / 0.2
Surveys · Bay of Biscay	1	18.2	0	—	1.3× / 0.8
Incidents · Gulf of Thailand	1	18	0	—	5.0× / 0.2
Incidents · Mozambique Channel	1	17.7	0	—	2.5× / 0.4
Other · Mediterranean Sea - Eastern Basin	1	17.6	0	—	5.0× / 0.2
Nav aids · South China Sea	1	16.8	1	16	5.0× / 0.2
Other · North Atlantic Ocean	1	16.5	0	—	0.6× / 1.6
Incidents · Alboran Sea	1	16.2	1	16	5.0× / 0.2
Incidents · Tyrrhenian Sea	1	16.2	1	16	2.5× / 0.4
Incidents · Arabian Sea	1	16	0	—	0.2× / 4.8
Volcanic · South Pacific Ocean	1	15.8	1	15	new / 0
Incidents · Mediterranean Sea - Western Basin	1	15.5	1	15	0.6× / 1.8
Spills · Caribbean Sea	1	14	0	—	5.0× / 0.2
Surveys · North Pacific Ocean	1	12.5	1	12	0.6× / 1.6
Missiles · Sea of Okhotsk	1	11.1	0	—	2.5× / 0.4
Surveys · Tasman Sea	1	9.9	1	9	2.5× / 0.4
Other · Inner Seas off the West Coast of Scotland	1	9.5	0	—	5.0× / 0.2
Incidents · English Channel	1	8.6	1	8	5.0× / 0.2
Other · Mediterranean Sea - Western Basin	1	6.9	0	—	new / 0
Missiles · Kara Sea	1	6.6	1	6	1.7× / 0.6
Exercises · Red Sea	1	6.3	1	47	0.8× / 1.2
Cable ops · Java Sea	1	5.5	1	5	5.0× / 0.2
Other · South China Sea	1	5.5	1	5	1.0× / 1
Incidents · Gulf of Alaska	1	4.2	0	—	new / 0
Missiles · Laccadive Sea	1	3.9	0	—	1.0× / 1
Derelicts · Arabian Sea	1	3	0	—	1.7× / 0.6
Derelicts · Coral Sea	1	3	0	—	0.8× / 1.2
Containers · Davis Strait	1	3	0	—	new / 0
Quakes · Eastern China Sea	1	3	0	—	new / 0
Debris · Gulf of Mexico	1	3	0	—	new / 0
Quakes · Gulf of Mexico	1	3	0	—	new / 0
Icebergs · Laptev Sea	1	3	0	—	0.4× / 2.6
Debris · North Atlantic Ocean	1	3	0	—	0.8× / 1.2
Quakes · North Atlantic Ocean	1	3	0	—	0.8× / 1.2
Derelicts · North Pacific Ocean	1	3	0	—	1.3× / 0.8
Quakes · South China Sea	1	3	0	—	5.0× / 0.2
Icebergs · South Pacific Ocean	1	3	0	—	new / 0
Derelicts · Tasman Sea	1	3	0	—	new / 0
Cable ops · Bay of Bengal	1	2.4	0	—	new / 0
Incidents · Bismarck Sea	1	2.3	0	—	0.5× / 2
Cable ops · Strait of Gibraltar	1	2.3	1	2	1.7× / 0.6
Derelicts · Bay of Bengal	1	1.8	0	—	2.5× / 0.4
Missiles · Arabian Sea	1	1.7	0	—	1.3× / 0.8
Cable ops · Gulf of Guinea	1	1.3	1	1	1.7× / 0.6
Debris · North Pacific Ocean	1	0.9	0	—	2.5× / 0.4
Incidents · Molukka Sea	1	0.1	0	—	5.0× / 0.2
Incidents · Timor Sea	1	0.1	0	—	0.6× / 1.6
Wrecks · South Atlantic Oceanlong running	0	186	6	522	0.0× / 1
Exercises · Aegean Sea	0	155	5	302	0.0× / 9
Wrecks · Arabian Sealong running	0	155	5	387	0.0× / 0.4
Nav aids · Beaufort Sealong running	0	124	4	446	0.0× / 1.4
Nav aids · Laccadive Sealong running	0	124	4	504	0.0× / 0.6
Ordnance · Bay of Biscay	0	93	3	134	— / 0
Other · Caribbean Sealong running	0	93	3	733	0.0× / 0.2
Surveys · Chukchi Sea	0	93	3	83	— / 0
Surveys · Kara Sealong running	0	93	3	477	0.0× / 0.8
Wrecks · Persian Gulflong running	0	93	3	622	— / 0
Wrecks · South China Sealong running	0	93	3	1,699	0.0× / 0.8
Nav aids · Arabian Sealong running	0	64.5	2	734	0.0× / 1.2
Nav aids · Bering Sea	0	62	2	312	0.0× / 0.4
Wrecks · Coral Sealong running	0	62	2	487	0.0× / 0.2
Wrecks · Laccadive Sea	0	62	2	256	0.0× / 0.4
Other · Persian Gulf	0	62	2	257	— / 0
Structures · South Atlantic Oceanlong running	0	62	2	459	0.0× / 1
Surveys · North Sea	0	38.5	1	44	0.0× / 2
Surveys · Coral Sea	0	38.1	1	77	— / 0
Missiles · Aegean Sea	0	31	1	302	— / 0
Nav aids · Andaman or Burma Sea	0	31	1	176	— / 0
Other · Arabian Sea	0	31	1	37	— / 0
Other · Arafura Sea	0	31	1	77	— / 0
Wrecks · Arafura Sea	0	31	1	183	— / 0
Nav aids · Barentsz Sea	0	31	1	353	— / 0
Other · Bay of Bengal	0	31	1	87	— / 0
Nav aids · Bay of Biscaylong running	0	31	1	459	— / 0
Surveys · Beaufort Sea	0	31	1	83	0.0× / 0.4
Other · Black Sea	0	31	1	226	0.0× / 0.2
War risk · Black Sealong running	0	31	1	588	— / 0
Surveys · East Siberian Sea	0	31	1	69	— / 0
Wrecks · Eastern China Sea	0	31	1	95	— / 0

Cite: seahazards.com Sea Ledger, 2023-10, 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.