Sea Ledger, April 2024

2024-04-01 to 2024-04-30 · archive

issued: 694
warning-days in force: 15,534
in force at month end: 488
sea × type cells: 253

baseline: same month, previous 5 years (2023-04, 2022-04, 2021-04, 2020-04, 2019-04)

By type

type	issued	warning-days	in force at end
Exercises	128	1,399.9	34
Icebergs	93	101.3	4
Incidents	85	1,133.3	25
Missiles	71	500.2	11
Nav aids	64	4,948.4	163
Surveys	64	2,661.6	87
Cable ops	48	1,162.6	41
Quakes	34	130.7	2
Other	23	669.4	26
Towing	22	52.1	2
Debris	19	84.8	3
Derelicts	14	98.2	3
Restricted	13	128.7	4
Spills	7	220	7
Wrecks	4	1,569.8	53
Piracy	2	4.4	1
Ordnance	1	96.9	3
War risk	1	59	2
Containers	1	3	0
Mines	0	120	4
Structures	0	30	1
Volcanic	0	360	12

By sea and type · 200 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Icebergs · South Atlantic Ocean	32	32.6	1	30	1.4× / 23
Icebergs · Southern Ocean	30	28.9	1	30	0.8× / 35.4
Icebergs · Labrador Sea	29	33.8	2	31	1.2× / 23.6
Exercises · North Pacific Ocean	26	374.3	9	65	1.0× / 27
Exercises · Bay of Bengalsurge	22	137.4	3	33	2.2× / 10.2
Towing · North Pacific Oceansurge	21	50.1	2	35	2.8× / 7.4
Missiles · Indian Oceansurge	18	156.7	4	30	4.3× / 4.2
Quakes · Philippine Seasurge	18	51	0	—	6.4× / 2.8
Incidents · North Atlantic Oceansurge	17	339.1	8	45	2.4× / 7.2
Missiles · North Atlantic Ocean	16	64	1	29	1.3× / 12.6
Incidents · South China Sea	14	146.7	2	45	0.8× / 18
Exercises · Arabian Sea	13	77.4	3	33	1.1× / 11.4
Nav aids · South Atlantic Oceanlong running	12	1,179.9	39	388	1.0× / 11.6
Restricted · Sea of Okhotsknew	12	74.6	2	20	new / 0
Surveys · Arabian Sea	11	371	12	109	1.0× / 10.6
Cable ops · North Atlantic Oceansurge	11	148.5	6	122	3.7× / 3
Missiles · North Pacific Oceanlong running	10	78.1	4	427	1.9× / 5.4
Debris · Indian Oceansurge	10	29.9	0	—	4.5× / 2.2
Nav aids · North Pacific Oceansurgelong running	9	227.1	7	755	2.3× / 4
Surveys · Indian Oceansurgelong running	8	197.8	9	431	2.0× / 4
Incidents · North Pacific Ocean	8	105.7	3	25	0.7× / 11.8
Incidents · Bay of Bengalsurge	8	62.2	2	45	10× / 0.8
Exercises · Laccadive Seasurge	8	56.2	1	31	2.9× / 2.8
Exercises · Philippine Seasurge	8	53.5	2	35	4.0× / 2
Exercises · South China Seasurge	8	50.4	2	46	13× / 0.6
Surveys · Black Seasurge	8	42.7	2	27	4.0× / 2
Exercises · South Pacific Ocean	8	40.1	1	32	0.9× / 9.2
Missiles · South Pacific Oceansurge	8	26.6	0	—	2.1× / 3.8
Exercises · Celtic Seasurge	8	8.3	1	26	2.1× / 3.8
Nav aids · North Atlantic Oceanlong running	7	436.5	14	1,111	1.3× / 5.6
Surveys · South Atlantic Ocean	7	294.4	8	266	0.4× / 17.4
Cable ops · Celtic Seanew	7	83	2	35	new / 0
Incidents · Indian Ocean	7	9.9	1	45	0.9× / 8
Missiles · Barentsz Sea	6	62.5	1	32	1.8× / 3.4
Cable ops · Gulf of Guineanew	6	34.9	1	34	new / 0
Derelicts · South Pacific Ocean	6	13.7	0	—	1.5× / 4
Cable ops · Arabian Sea	5	198.4	8	112	1.4× / 3.6
Incidents · South Pacific Ocean	5	87.5	2	39	1.1× / 4.4
Cable ops · Indian Oceansurge	5	67.3	2	39	25× / 0.2
Surveys · Caribbean Seasurge	5	41.3	2	34	3.1× / 1.6
Exercises · Bay of Biscaysurge	5	9.8	0	—	2.5× / 2
Cable ops · North Pacific Oceansurge	4	75.1	2	50	2.5× / 1.6
Nav aids · North Sea	4	60.6	2	103	0.6× / 7
Nav aids · Coral Sea	4	31.6	0	—	0.9× / 4.6
Exercises · Sea of Okhotsksurge	4	24.3	2	14	4.0× / 1
Incidents · Caribbean Sea	4	20.1	2	18	1.1× / 3.6
Quakes · South Pacific Ocean	4	14.1	0	—	0.4× / 9.6
Quakes · North Pacific Ocean	4	12	0	—	1.3× / 3
Exercises · Andaman or Burma Sea	4	11.1	0	—	0.9× / 4.4
Incidents · Coral Sea	4	1.1	0	—	1.1× / 3.6
Nav aids · Caribbean Sealong running	3	1,025.8	33	1,169	1.5× / 2
Nav aids · Gulf of Mexicolong running	3	310.5	9	1,124	1.7× / 1.8
Nav aids · South Pacific Oceanlong running	3	308.5	11	768	0.7× / 4.6
Surveys · South Pacific Ocean	3	165.6	6	81	1.4× / 2.2
Exercises · Black Sealong running	3	110	2	769	0.3× / 12
Nav aids · English Channel	3	98.9	4	179	1.7× / 1.8
Nav aids · Bay of Biscaysurgelong running	3	83.3	3	641	15× / 0.2
Other · North Atlantic Ocean	3	74.6	3	35	0.4× / 7.6
Incidents · South Atlantic Ocean	3	63	1	46	0.4× / 6.8
Other · North Pacific Oceansurge	3	43.3	2	101	2.5× / 1.2
Derelicts · North Atlantic Ocean	3	35.9	1	182	0.9× / 3.2
Cable ops · South Pacific Ocean	3	16.1	1	18	1.7× / 1.8
Nav aids · Inner Seas off the West Coast of Scotland	3	15.6	0	—	1.3× / 2.4
Cable ops · Singapore Straitnew	3	15.5	1	15	new / 0
Missiles · Japan Sea	3	14	0	—	1.1× / 2.6
Missiles · Bay of Biscaynew	3	7	0	—	new / 0
Wrecks · Arabian Sea	2	211.3	8	350	2.0× / 1
Surveys · Persian Gulflong running	2	159.1	5	620	0.2× / 8.6
Nav aids · Indian Ocean	2	97.4	2	251	0.8× / 2.4
Other · Indian Ocean	2	63.5	2	105	1.7× / 1.2
Incidents · Gulf of Mexico	2	61.5	1	30	1.4× / 1.4
Exercises · Japan Sea	2	46.9	1	34	1.4× / 1.4
Surveys · Gulf of Guineanew	2	44.4	1	37	new / 0
Spills · North Pacific Ocean	2	36	1	34	0.6× / 3.4
Spills · Gulf of Mexico	2	30	1	42	0.4× / 4.8
Surveys · Mediterranean Sea - Western Basin	2	28	2	89	1.0× / 2
Surveys · North Pacific Ocean	2	28	0	—	1.7× / 1.2
Spills · The Coastal Waters of Southeast Alaska and British Columbia	2	28	1	16	1.7× / 1.2
Exercises · North Atlantic Ocean	2	20.3	1	20	0.4× / 5.4
Exercises · Red Sea	2	15.5	2	11	2.5× / 0.8
Other · Norwegian Seanew	2	14.6	2	7	new / 0
Missiles · South Atlantic Ocean	2	12.3	0	—	2.5× / 0.8
Debris · Coral Sea	2	6	0	—	1.3× / 1.6
Quakes · Indian Ocean	2	6	0	—	0.6× / 3.4
Icebergs · Kara Sea	2	6	0	—	1.7× / 1.2
Quakes · Solomon Sea	2	6	0	—	2.0× / 1
Derelicts · Celtic Seanew	2	4.6	0	—	new / 0
Debris · Celtic Seanew	2	4.1	1	19	new / 0
Debris · South Pacific Ocean	2	3.7	1	3	1.1× / 1.8
Other · Andaman or Burma Sea	2	3.6	1	8	5.0× / 0.4
Missiles · Bay of Bengalnew	2	3.4	0	—	new / 0
Nav aids · Great Australian Bight	2	2.6	2	1	2.5× / 0.8
Incidents · Ionian Sea	2	0.1	0	—	10× / 0.2
Surveys · North Atlantic Ocean	1	225.3	6	118	0.1× / 7.8
Wrecks · North Atlantic Ocean	1	130	5	195	new / 0
Surveys · Bay of Bengal	1	106.9	3	56	0.3× / 3
Nav aids · Celtic Sea	1	106.5	3	232	1.3× / 0.8
Surveys · Laccadive Sealong running	1	105.5	4	808	1.3× / 0.8
Other · Caribbean Sealong running	1	101.3	3	915	2.5× / 0.4
Surveys · Gulf of Mexico	1	97	3	272	1.7× / 0.6
Nav aids · Laccadive Sea	1	63	2	320	2.5× / 0.4
Surveys · Timor Sea	1	62.9	2	59	new / 0
War risk · Black Sealong running	1	59	2	770	new / 0
Spills · North Atlantic Oceanlong running	1	55	2	649	0.8× / 1.2
Cable ops · Philippine Sea	1	43.5	2	46	1.7× / 0.6
Incidents · Mediterranean Sea - Eastern Basin	1	37.5	0	—	0.5× / 2.2
Other · South Atlantic Ocean	1	36.5	2	153	1.3× / 0.8
Nav aids · Irish Sea and St. George's Channel	1	35.4	2	142	1.3× / 0.8
Incidents · Arabian Sea	1	33.9	1	46	0.7× / 1.4
Other · Bay of Bengal	1	33	1	269	2.5× / 0.4
Debris · Bay of Biscaylong running	1	33	1	601	5.0× / 0.2
Nav aids · Andaman or Burma Sea	1	31.4	2	358	2.5× / 0.4
Incidents · Tyrrhenian Sea	1	31	0	—	new / 0
Other · Black Sealong running	1	30	1	408	1.7× / 0.6
Missiles · East Siberian Sea	1	29.5	0	—	5.0× / 0.2
Other · Coral Sea	1	27.1	1	27	1.7× / 0.6
Other · Mediterranean Sea - Eastern Basin	1	27.1	1	32	1.7× / 0.6
Cable ops · Eastern China Sea	1	25.5	1	25	new / 0
Surveys · Gulf of California	1	25.1	1	25	new / 0
Nav aids · Gulf of Oman	1	23.3	1	23	new / 0
Incidents · Bay of Biscay	1	22	1	22	new / 0
Incidents · Java Sea	1	19.6	0	—	1.0× / 1
Other · Beaufort Sea	1	19	1	18	new / 0
Derelicts · Bass Strait	1	18.7	1	18	new / 0
Incidents · Mozambique Channel	1	15.6	1	15	2.5× / 0.4
Wrecks · English Channel	1	13.9	1	13	1.7× / 0.6
Surveys · Great Australian Bight	1	13.8	0	—	1.3× / 0.8
Cable ops · Laccadive Sea	1	13.5	1	13	new / 0
Surveys · Irish Sea and St. George's Channel	1	12.8	1	12	5.0× / 0.2
Surveys · Andaman or Burma Sea	1	12.5	0	—	1.7× / 0.6
Surveys · Philippine Sea	1	11.4	0	—	1.3× / 0.8
Surveys · Bay of Biscay	1	11.1	0	—	5.0× / 0.2
Surveys · Ionian Sea	1	9.9	0	—	2.5× / 0.4
Other · Irish Sea and St. George's Channel	1	8.5	1	8	new / 0
Exercises · Tasman Sea	1	8.5	0	—	1.7× / 0.6
Surveys · North Sea	1	8.2	1	8	0.5× / 2.2
Exercises · South Atlantic Ocean	1	7	0	—	0.1× / 7
Incidents · Laccadive Sea	1	6.9	0	—	0.4× / 2.6
Ordnance · Philippine Sea	1	6.9	0	—	new / 0
Other · Gulf of Alaska	1	5.9	0	—	5.0× / 0.2
Missiles · Gulf of Mexico	1	5.4	0	—	0.6× / 1.6
Restricted · North Pacific Ocean	1	5.4	1	5	new / 0
Incidents · Bismarck Sea	1	5.3	0	—	2.5× / 0.4
Cable ops · Mediterranean Sea - Western Basin	1	5.3	1	5	0.6× / 1.6
Nav aids · Bristol Channel	1	4.3	1	4	5.0× / 0.2
Surveys · Norwegian Sea	1	4.1	1	4	0.6× / 1.6
Other · South China Sea	1	3.5	0	—	new / 0
Derelicts · Mozambique Channel	1	3.3	0	—	new / 0
Debris · Philippine Sea	1	3.3	0	—	new / 0
Quakes · Gulf of California	1	3	0	—	new / 0
Piracy · Makassar Strait	1	3	0	—	new / 0
Quakes · Molukka Sea	1	3	0	—	1.3× / 0.8
Debris · Mozambique Channel	1	3	0	—	new / 0
Containers · North Atlantic Ocean	1	3	0	—	2.5× / 0.4
Other · South Pacific Ocean	1	3	0	—	0.8× / 1.2
Exercises · Coral Sea	1	2.4	0	—	0.7× / 1.4
Derelicts · Banda Sea	1	2	1	1	new / 0
Towing · The Coastal Waters of Southeast Alaska and British Columbia	1	2	0	—	new / 0
Missiles · Laccadive Sea	1	1.9	0	—	1.0× / 1
Exercises · Mozambique Channel	1	1.7	0	—	0.8× / 1.2
Piracy · Arabian Sea	1	1.4	1	1	new / 0
Incidents · Labrador Sea	1	1.2	0	—	1.3× / 0.8
Exercises · Malacca Strait	1	0.8	0	—	new / 0
Quakes · South Atlantic Ocean	1	0.4	1	0	0.5× / 2
Incidents · Bass Strait	1	0.2	0	—	new / 0
Quakes · South China Sea	1	0.1	0	—	1.7× / 0.6
Incidents · Timor Sea	1	0.1	0	—	1.3× / 0.8
Volcanic · Philippine Sealong running	0	300	10	1,229	— / 0
Surveys · The Northwestern Passageslong running	0	210	7	620	— / 0
Wrecks · Persian Gulflong running	0	180	6	804	0.0× / 0.2
Nav aids · South China Sea	0	180	6	148	— / 0
Wrecks · The Northwestern Passageslong running	0	180	6	971	— / 0
Cable ops · Persian Gulflong running	0	150	5	405	0.0× / 0.4
Exercises · Gulf of Mexico	0	140	0	—	0.0× / 1.2
Mines · Black Sealong running	0	120	4	796	— / 0
Wrecks · Caribbean Sealong running	0	120	4	415	0.0× / 0.6
Exercises · Aegean Sea	0	90	3	117	0.0× / 8.8
Surveys · Arctic Ocean	0	90	3	188	— / 0
Ordnance · Bay of Biscay	0	90	3	316	— / 0
Nav aids · Beaufort Sealong running	0	90	3	628	— / 0
Nav aids · Bering Sealong running	0	90	3	494	0.0× / 0.2
Wrecks · South China Sealong running	0	90	3	1,881	0.0× / 0.6
Wrecks · South Pacific Oceanlong running	0	90	3	393	0.0× / 0.6
Cable ops · Sulu Sea	0	71	2	46	0.0× / 0.2
Wrecks · Hudson Baylong running	0	67.3	1	550	— / 0
Nav aids · Arabian Sealong running	0	60	2	916	0.0× / 0.4
Wrecks · Bay of Bengal	0	60	2	279	0.0× / 0.2
Other · Bay of Biscaylong running	0	60	2	468	0.0× / 0.4
Spills · Caribbean Sea	0	60	2	75	0.0× / 0.2
Surveys · Chukchi Sea	0	60	2	265	— / 0
Wrecks · Coral Sealong running	0	60	2	669	— / 0
Nav aids · Gulf of Alaska	0	60	2	57	0.0× / 1
Nav aids · Hudson Strait	0	60	2	291	— / 0
Surveys · Kara Sealong running	0	60	2	645	— / 0
Wrecks · Kara Sea	0	60	2	196	— / 0
Wrecks · Laccadive Sealong running	0	60	2	438	0.0× / 0.2
Volcanic · North Pacific Ocean	0	60	2	120	— / 0
Nav aids · Persian Gulflong running	0	60	2	707	0.0× / 0.6
Other · Persian Gulflong running	0	60	2	439	0.0× / 0.4
Wrecks · South Atlantic Ocean	0	60	2	181	0.0× / 1.2

Cite: seahazards.com Sea Ledger, 2024-04, 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.