Sea Ledger, December 2023

2023-12-01 to 2023-12-31 · archive

issued: 634
warning-days in force: 14,619
in force at month end: 450
sea × type cells: 231

baseline: same month, previous 5 years (2022-12, 2021-12, 2020-12, 2019-12, 2018-12)

By type

type	issued	warning-days	in force at end
Exercises	107	1,192.2	23
Icebergs	94	101.1	4
Incidents	83	952.6	33
Surveys	70	2,645.1	81
Missiles	70	475.3	8
Quakes	69	226.6	4
Nav aids	51	4,851.9	166
Cable ops	24	723	25
Derelicts	20	129.9	5
Other	17	566.6	16
Spills	13	237	5
Debris	10	52.4	2
Piracy	3	9.8	0
Wrecks	2	1,677.7	53
Containers	1	3	0
Volcanic	0	341	11
Mines	0	124	4
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	31	35.3	2	32	1.0× / 31.4
Icebergs · Southern Ocean	31	32.9	1	31	1.0× / 32
Icebergs · South Atlantic Ocean	31	29.9	1	31	1.3× / 24.2
Quakes · Philippine Seasurge	27	75.1	0	—	7.9× / 3.4
Missiles · North Atlantic Oceansurge	26	71.1	1	34	2.2× / 12
Surveys · South Atlantic Ocean	20	351.3	10	220	1.2× / 16.6
Incidents · South China Sea	18	181.8	8	50	0.6× / 30.8
Quakes · South Pacific Ocean	17	50.2	1	33	1.6× / 10.6
Exercises · Bay of Bengal	16	176.8	2	38	1.3× / 12.4
Surveys · South Pacific Oceansurge	15	138.6	4	39	38× / 0.4
Missiles · South Pacific Ocean	15	72.6	4	37	1.9× / 7.8
Exercises · North Pacific Ocean	14	221.8	9	65	0.7× / 19
Cable ops · North Atlantic Oceansurge	14	151	8	80	4.1× / 3.4
Incidents · North Atlantic Ocean	13	223	5	47	1.1× / 12.2
Nav aids · South Atlantic Oceansurgelong running	12	1,307	48	506	2.9× / 4.2
Missiles · North Pacific Oceansurge	10	79.8	2	306	2.2× / 4.6
Exercises · Celtic Seasurge	10	10.1	0	—	3.3× / 3
Exercises · South Atlantic Ocean	9	124.8	1	52	1.3× / 7.2
Exercises · Arabian Sea	9	76.8	1	34	0.6× / 14.6
Exercises · Laccadive Seasurge	9	60	1	33	2.4× / 3.8
Derelicts · North Atlantic Ocean	8	72.3	2	61	1.2× / 6.8
Incidents · South Pacific Ocean	8	28.9	4	25	1.7× / 4.8
Surveys · Indian Oceansurge	7	226.8	9	310	2.5× / 2.8
Missiles · Barentsz Sea	7	60.8	0	—	1.3× / 5.6
Exercises · Andaman or Burma Seasurge	7	36.3	0	—	4.4× / 1.6
Incidents · Gulf of Mexicosurge	6	70.5	3	46	5.0× / 1.2
Exercises · South Pacific Ocean	6	19.6	0	—	0.8× / 7.8
Other · North Pacific Ocean	6	14.4	0	—	0.8× / 7.2
Surveys · Arabian Sea	5	361.6	12	66	0.7× / 7.4
Surveys · North Atlantic Ocean	5	330.6	8	364	0.5× / 10.8
Quakes · Coral Seasurge	5	43	1	39	5.0× / 1
Incidents · North Pacific Ocean	5	38.4	3	46	0.3× / 15
Quakes · North Pacific Ocean	5	15.3	0	—	0.6× / 8.6
Nav aids · North Atlantic Oceanlong running	4	357.8	12	990	0.7× / 5.6
Nav aids · Gulf of Mexicosurgelong running	4	289.4	9	1,003	3.3× / 1.2
Nav aids · Coral Sea	4	172.4	7	252	1.3× / 3
Nav aids · South China Seanew	4	106.5	4	77	new / 0
Spills · North Atlantic Oceansurgelong running	4	105	2	528	2.9× / 1.4
Surveys · Gulf of Mexicosurge	4	93	3	151	6.7× / 0.6
Missiles · Indian Ocean	4	74.4	0	—	1.4× / 2.8
Exercises · North Atlantic Ocean	4	49.1	1	126	0.8× / 5
Incidents · Indian Ocean	4	44.3	0	—	0.7× / 5.6
Other · North Atlantic Ocean	4	12.7	0	—	1.2× / 3.4
Quakes · Indian Oceansurge	4	7.7	2	9	2.2× / 1.8
Debris · English Channelsurge	4	4.8	0	—	20× / 0.2
Nav aids · Caribbean Sealong running	3	929.2	30	1,048	0.9× / 3.4
Nav aids · North Pacific Oceanlong running	3	231.3	8	634	0.9× / 3.4
Nav aids · English Channel	3	84.3	3	58	1.5× / 2
Cable ops · Caribbean Seasurge	3	71.9	1	35	3.0× / 1
Incidents · South Atlantic Ocean	3	58.3	1	49	0.5× / 5.6
Surveys · Bay of Bengal	3	55.2	3	101	0.7× / 4.6
Nav aids · North Sea	3	54.5	2	72	0.3× / 10
Incidents · Caribbean Sea	3	41.1	0	—	1.3× / 2.4
Surveys · Bass Straitsurge	3	38.1	1	269	3.0× / 1
Spills · The Coastal Waters of Southeast Alaska and British Columbiasurge	3	34	2	42	3.0× / 1
Incidents · Arabian Sea	3	28.2	3	48	0.7× / 4.6
Incidents · Mediterranean Sea - Eastern Basin	3	27.8	2	48	1.5× / 2
Nav aids · Inner Seas off the West Coast of Scotland	3	19.8	0	—	1.4× / 2.2
Exercises · Sulu Seasurge	3	16.3	0	—	15× / 0.2
Exercises · Bay of Biscaysurge	3	15.3	0	—	3.0× / 1
Missiles · South China Seasurge	3	14.4	0	—	3.8× / 0.8
Exercises · Japan Seasurge	3	6.8	0	—	2.1× / 1.4
Derelicts · Caribbean Sea	3	4.6	0	—	1.9× / 1.6
Nav aids · South Pacific Oceanlong running	2	239	8	647	0.5× / 4.2
Exercises · Aegean Sea	2	157.2	5	363	0.2× / 8.8
Surveys · Caribbean Sealong running	2	61.9	2	427	1.4× / 1.4
Cable ops · South Atlantic Ocean	2	56.8	3	191	5.0× / 0.4
Surveys · Mediterranean Sea - Eastern Basin	2	37.5	2	79	0.6× / 3.2
Spills · North Pacific Ocean	2	31	0	—	0.6× / 3.4
Missiles · East Siberian Seanew	2	28.2	0	—	new / 0
Other · Davis Strait	2	28	0	—	2.0× / 1
Spills · Gulf of Mexico	2	28	0	—	0.6× / 3.2
Exercises · Philippine Sea	2	20.6	0	—	0.8× / 2.6
Nav aids · Gulf of Alaska	2	14.1	1	16	2.0× / 1
Quakes · South Atlantic Ocean	2	8.3	0	—	0.8× / 2.4
Exercises · Indian Ocean	2	7.5	0	—	0.9× / 2.2
Cable ops · North Pacific Ocean	2	6.8	0	—	2.0× / 1
Quakes · Solomon Sea	2	6	0	—	2.5× / 0.8
Quakes · Southern Ocean	2	6	0	—	1.4× / 1.4
Piracy · Indian Oceannew	2	5.8	0	—	new / 0
Incidents · Laccadive Sea	2	5.7	1	7	0.7× / 2.8
Derelicts · South Pacific Ocean	2	5.2	1	20	0.6× / 3.6
Debris · Indian Ocean	2	4.6	1	27	2.5× / 0.8
Derelicts · Celtic Seanew	2	3.5	0	—	new / 0
Incidents · Bay of Bengal	2	2.7	0	—	1.0× / 2
Incidents · Celtic Sea	2	0.3	0	—	10× / 0.2
Wrecks · Arabian Sealong running	1	203.5	7	448	1.0× / 1
Other · South Atlantic Ocean	1	86.3	3	243	1.0× / 1
Surveys · Laccadive Sealong running	1	75.5	3	687	1.3× / 0.8
Wrecks · South Pacific Ocean	1	74.1	3	272	5.0× / 0.2
Exercises · Black Sealong running	1	71.8	2	648	0.1× / 11.8
Surveys · Black Sea	1	64.3	2	332	0.8× / 1.2
Incidents · Philippine Sea	1	51.8	0	—	1.0× / 1
Surveys · Gulf of Guinea	1	33.3	1	47	new / 0
Missiles · Aegean Sea	1	32.1	1	363	1.7× / 0.6
Nav aids · The Coastal Waters of Southeast Alaska and British Columbia	1	32	1	294	2.5× / 0.4
Other · Arabian Sea	1	29.5	0	—	1.7× / 0.6
Incidents · Andaman or Burma Sea	1	21.4	0	—	5.0× / 0.2
Nav aids · Irish Sea and St. George's Channel	1	21.4	1	21	1.0× / 1
Surveys · South China Sea	1	20.8	0	—	5.0× / 0.2
Incidents · Gulf of Thailand	1	19.3	0	—	0.5× / 2
Incidents · Ionian Sea	1	16	0	—	new / 0
Exercises · Sea of Okhotsk	1	16	0	—	new / 0
Incidents · Alboran Sea	1	15.5	0	—	new / 0
Spills · Bering Sea	1	14	1	35	new / 0
Spills · Chukchi Sea	1	14	0	—	5.0× / 0.2
Cable ops · Ligurian Sea	1	13.3	1	13	new / 0
Nav aids · Great Australian Bight	1	12.7	1	12	0.6× / 1.6
Exercises · White Sea	1	12.7	0	—	new / 0
Incidents · Bali Sea	1	11.2	1	11	new / 0
Incidents · Makassar Strait	1	11	1	10	new / 0
Nav aids · Philippine Sea	1	10.7	1	10	new / 0
Incidents · Coral Sea	1	9.7	1	47	0.2× / 4.6
Exercises · Tasman Sea	1	6.9	0	—	new / 0
Cable ops · Indian Ocean	1	6.4	0	—	1.7× / 0.6
Exercises · Barentsz Sea	1	6.1	0	—	new / 0
Exercises · South China Sea	1	6	0	—	0.6× / 1.8
Cable ops · Irish Sea and St. George's Channel	1	5.8	0	—	1.0× / 1
Other · Indian Ocean	1	5.6	1	5	1.7× / 0.6
Exercises · Gulf of Oman	1	5	0	—	new / 0
Missiles · Coral Sea	1	4.2	0	—	new / 0
Piracy · Arabian Sea	1	4	0	—	new / 0
Derelicts · Arabian Sea	1	3	0	—	0.4× / 2.8
Quakes · Banda Sea	1	3	0	—	0.6× / 1.6
Quakes · Bay of Bengal	1	3	0	—	new / 0
Derelicts · Coral Sea	1	3	0	—	new / 0
Quakes · Gulf of Aden	1	3	0	—	new / 0
Derelicts · Mozambique Channel	1	3	0	—	1.7× / 0.6
Containers · North Atlantic Ocean	1	3	0	—	5.0× / 0.2
Debris · North Atlantic Ocean	1	3	0	—	0.4× / 2.4
Quakes · North Atlantic Ocean	1	3	0	—	5.0× / 0.2
Debris · North Pacific Ocean	1	3	0	—	1.7× / 0.6
Quakes · Norwegian Sea	1	3	0	—	5.0× / 0.2
Debris · South Atlantic Ocean	1	3	0	—	0.6× / 1.6
Derelicts · South China Sea	1	3	0	—	0.4× / 2.4
Debris · South Pacific Ocean	1	3	0	—	1.3× / 0.8
Icebergs · South Pacific Ocean	1	3	0	—	2.5× / 0.4
Other · Mozambique Channel	1	2.2	0	—	5.0× / 0.2
Missiles · Laccadive Sea	1	1.9	0	—	1.3× / 0.8
Derelicts · Gulf of Mexico	1	1.3	1	1	0.6× / 1.8
Incidents · Solomon Sea	1	0.7	0	—	1.7× / 0.6
Other · South China Sea	1	0.7	0	—	2.5× / 0.4
Incidents · Mozambique Channel	1	0.3	0	—	1.7× / 0.6
Exercises · Mozambique Channel	1	0.2	0	—	1.7× / 0.6
Incidents · Eastern China Sea	1	0.1	0	—	2.5× / 0.4
Volcanic · Philippine Sealong running	0	310	10	1,108	0.0× / 0.8
Surveys · The Northwestern Passageslong running	0	217	7	499	— / 0
Surveys · Persian Gulflong running	0	206	5	499	0.0× / 5
Wrecks · South Atlantic Oceanlong running	0	200.7	6	583	0.0× / 1
Wrecks · The Northwestern Passageslong running	0	186	6	850	— / 0
Cable ops · Persian Gulf	0	170.4	5	284	— / 0
Mines · Black Sealong running	0	124	4	675	— / 0
Wrecks · Caribbean Sea	0	124	4	294	0.0× / 0.2
Nav aids · Laccadive Sealong running	0	124	4	565	0.0× / 0.6
Wrecks · North Atlantic Ocean	0	124	4	74	0.0× / 0.4
Wrecks · Persian Gulflong running	0	124	4	683	0.0× / 1.2
Wrecks · Hudson Baylong running	0	122.2	3	429	— / 0
Cable ops · Arabian Sea	0	93	3	108	0.0× / 2.8
Ordnance · Bay of Biscay	0	93	3	195	— / 0
Nav aids · Beaufort Sealong running	0	93	3	507	— / 0
Other · Caribbean Sealong running	0	93	3	794	0.0× / 0.2
Nav aids · Indian Ocean	0	93	3	130	0.0× / 0.8
Wrecks · South China Sealong running	0	93	3	1,760	0.0× / 1
Surveys · Kara Sealong running	0	89.8	2	538	— / 0
Nav aids · Persian Gulflong running	0	77.4	2	586	0.0× / 0.8
Surveys · Chukchi Sea	0	65.4	2	144	— / 0
Nav aids · Arabian Sealong running	0	62	2	795	0.0× / 1
Surveys · Arctic Ocean	0	62	2	67	— / 0
Wrecks · Bay of Bengal	0	62	2	158	— / 0
Nav aids · Bay of Biscaylong running	0	62	2	520	0.0× / 0.2
Other · Bay of Biscay	0	62	2	347	— / 0
Nav aids · Bering Sealong running	0	62	2	373	0.0× / 1
Nav aids · Celtic Sea	0	62	2	111	0.0× / 1.8
Wrecks · Coral Sealong running	0	62	2	548	— / 0
Nav aids · Hudson Strait	0	62	2	170	0.0× / 0.2
Wrecks · Kara Sea	0	62	2	75	— / 0
Wrecks · Laccadive Sea	0	62	2	317	0.0× / 0.2
Other · Persian Gulf	0	62	2	318	0.0× / 0.4
Structures · South Atlantic Oceanlong running	0	62	2	520	0.0× / 1
Missiles · Philippine Sea	0	35.8	0	—	0.0× / 0.6
Nav aids · Andaman or Burma Sea	0	31	1	237	— / 0
Other · Arafura Sea	0	31	1	138	— / 0
Wrecks · Arafura Sea	0	31	1	244	— / 0
Nav aids · Arctic Ocean	0	31	1	79	— / 0
Nav aids · Bass Strait	0	31	1	81	0.0× / 1.4
Other · Bay of Bengal	0	31	1	148	— / 0
Debris · Bay of Biscaylong running	0	31	1	480	0.0× / 0.2
Surveys · Beaufort Sea	0	31	1	144	0.0× / 0.2
Other · Black Sea	0	31	1	287	— / 0
War risk · Black Sealong running	0	31	1	649	— / 0
Exercises · Caribbean Sea	0	31	1	100	0.0× / 0.6
Cable ops · Celebes Sea	0	31	1	53	— / 0
Other · Coral Sea	0	31	1	54	0.0× / 1
Surveys · Coral Sea	0	31	1	138	— / 0
Wrecks · Eastern China Sea	0	31	1	156	— / 0
Other · English Channel	0	31	1	342	0.0× / 0.2
Nav aids · Gulf of Californialong running	0	31	1	625	— / 0
Wrecks · Gulf of Mexicolong running	0	31	1	658	— / 0
Nav aids · Gulf of St. Lawrence	0	31	1	132	0.0× / 0.2
Nav aids · Hudson Baylong running	0	31	1	473	— / 0

Cite: seahazards.com Sea Ledger, 2023-12, 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.