Sea Ledger, April 2017

2017-04-01 to 2017-04-30 · archive

issued: 619
warning-days in force: 11,101
in force at month end: 361
sea × type cells: 242

baseline: same month, previous 5 years (2016-04, 2015-04, 2014-04, 2013-04, 2012-04)

By type

type	issued	warning-days	in force at end
Incidents	144	1,429.7	42
Exercises	102	1,228.9	43
Surveys	79	1,919.7	67
Nav aids	74	2,714.5	76
Icebergs	62	69.3	3
Missiles	28	324.8	10
Quakes	28	85	5
Derelicts	20	102.8	4
Wrecks	17	1,496.5	51
Piracy	16	146.6	6
Spills	15	183.6	7
Cable ops	11	437.7	15
Debris	9	25.1	1
Other	6	453.3	16
Volcanic	3	124.6	5
Restricted	2	179	5
Ordnance	2	137.7	4
Containers	1	5.2	0
Structures	0	30	1
Storms	0	6.6	0

By sea and type · 200 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Icebergs · Southern Oceansurge	31	32	1	30	19× / 1.6
Exercises · North Pacific Oceansurge	29	132.5	6	66	2.0× / 14.2
Incidents · North Pacific Ocean	28	243	6	35	1.1× / 24.6
Incidents · South China Sea	27	223.7	10	39	1.9× / 14
Icebergs · North Atlantic Oceansurge	27	33.5	0	—	2.3× / 12
Surveys · South Atlantic Oceansurge	23	194.3	5	326	3.0× / 7.6
Incidents · Mediterranean Sea - Eastern Basin	22	358.9	11	42	1.7× / 12.8
Incidents · North Atlantic Ocean	14	179.4	1	40	0.8× / 16.8
Exercises · Bay of Bengal	14	68	6	51	1.9× / 7.2
Quakes · South Pacific Ocean	12	34.7	2	25	1.0× / 12.4
Nav aids · North Sealong running	11	224.4	5	526	1.0× / 11
Surveys · North Atlantic Oceansurgelong running	10	236.4	12	1,062	4.2× / 2.4
Nav aids · South Pacific Oceansurge	10	179.9	5	247	13× / 0.8
Surveys · Arabian Seasurge	10	152.5	3	52	7.1× / 1.4
Incidents · South Atlantic Ocean	10	76.3	0	—	1.6× / 6.4
Nav aids · South Atlantic Ocean	9	215.1	8	190	1.3× / 7
Nav aids · Coral Sealong running	9	165.4	5	1,108	1.8× / 5
Missiles · Black Seasurge	9	88	3	36	5.6× / 1.6
Missiles · North Pacific Ocean	8	77.5	3	73	1.7× / 4.8
Exercises · Arabian Sea	8	58.1	1	30	1.3× / 6
Incidents · South Pacific Ocean	8	34.1	1	43	0.9× / 8.6
Nav aids · North Atlantic Oceanlong running	7	243.5	5	1,439	1.2× / 6
Wrecks · North Seanew	7	155.2	6	65	new / 0
Exercises · Black Sea	7	122.2	3	151	0.6× / 11.6
Incidents · Gulf of Mexico	7	85.4	4	31	1.8× / 3.8
Exercises · Indian Oceansurge	7	30.4	2	16	8.8× / 0.8
Piracy · Gulf of Guineasurge	7	29.4	4	32	2.3× / 3
Quakes · Philippine Seasurge	7	19.5	1	22	3.5× / 2
Exercises · North Atlantic Ocean	6	81	4	94	1.2× / 5
Spills · Gulf of Mexico	6	69	2	42	1.4× / 4.2
Nav aids · Inner Seas off the West Coast of Scotland	6	59.9	2	179	1.8× / 3.4
Surveys · Norwegian Seanew	6	59.6	6	18	new / 0
Wrecks · South China Seasurgelong running	5	354.9	13	1,084	25× / 0.2
Spills · North Atlantic Oceansurge	5	56	4	31	8.3× / 0.6
Incidents · Philippine Sea	5	44.8	3	41	1.7× / 3
Incidents · Coral Sea	5	7.1	1	29	1.3× / 4
Missiles · North Atlantic Ocean	4	93.2	3	45	0.7× / 6
Surveys · Caribbean Seasurge	4	46.1	2	108	6.7× / 0.6
Exercises · Yellow Sea	4	19.3	1	23	0.4× / 11
Icebergs · Labrador Sea	4	3.8	2	3	0.3× / 14
Exercises · Aegean Seasurge	3	332.4	11	122	3.0× / 1
Nav aids · North Pacific Oceansurge	3	183.6	5	245	5.0× / 0.6
Surveys · South China Seasurge	3	102.1	3	46	7.5× / 0.4
Cable ops · North Atlantic Ocean	3	85.8	4	70	0.6× / 5
Surveys · Mediterranean Sea - Eastern Basin	3	53.6	3	57	1.5× / 2
Incidents · Caribbean Sea	3	41.1	1	38	0.9× / 3.4
Derelicts · South China Seasurge	3	38	1	100	3.8× / 0.8
Surveys · North Seasurge	3	23.6	1	74	5.0× / 0.6
Piracy · Arabian Seasurge	3	21	0	—	3.0× / 1
Exercises · South Atlantic Ocean	3	20	1	30	0.5× / 6.2
Derelicts · Indian Ocean	3	12.5	1	27	0.5× / 5.8
Exercises · Baltic Sea	3	11.8	1	30	1.1× / 2.6
Quakes · Indian Ocean	3	7.6	1	21	0.6× / 5.4
Derelicts · Yellow Seasurge	3	7.4	0	—	15× / 0.2
Surveys · Aegean Seasurge	3	5.2	0	—	3.8× / 0.8
Nav aids · Gulf of Mexicolong running	2	181.8	4	1,170	1.0× / 2
Surveys · Bay of Bengal	2	116	3	296	1.0× / 2
Volcanic · Philippine Sealong running	2	70.7	3	1,827	5.0× / 0.4
Nav aids · Irish Sea and St. George's Channel	2	68.1	1	81	0.8× / 2.4
Piracy · Indian Ocean	2	64.7	2	35	3.3× / 0.6
Ordnance · North Sea	2	60	2	57	3.3× / 0.6
Nav aids · Bay of Bengal	2	54.5	2	131	3.3× / 0.6
Surveys · Black Sea	2	51.5	2	40	1.7× / 1.2
Surveys · Gulf of Mexico	2	45.2	2	80	5.0× / 0.4
Nav aids · English Channel	2	40.6	0	—	0.9× / 2.2
Exercises · Laccadive Sea	2	35.2	1	32	1.1× / 1.8
Exercises · Gulf of Mexico	2	31.8	0	—	1.3× / 1.6
Other · North Sea	2	28.2	1	21	1.3× / 1.6
Incidents · Mediterranean Sea - Western Basinnew	2	27.4	1	38	new / 0
Incidents · Arabian Sea	2	25.9	1	47	0.8× / 2.6
Derelicts · Bay of Bengal	2	21.5	0	—	5.0× / 0.4
Missiles · Japan Sea	2	15	0	—	1.7× / 1.2
Piracy · Red Seanew	2	14	0	—	new / 0
Nav aids · Laccadive Sea	2	13.1	1	11	2.0× / 1
Nav aids · Ionian Seanew	2	12.8	1	23	new / 0
Cable ops · South China Sea	2	11.9	1	26	0.8× / 2.6
Exercises · Adriatic Sea	2	10.2	0	—	2.5× / 0.8
Exercises · Alboran Seanew	2	8.3	1	90	new / 0
Exercises · South Pacific Ocean	2	8.3	1	16	0.3× / 5.8
Exercises · Andaman or Burma Sea	2	7	1	9	1.3× / 1.6
Exercises · Mediterranean Sea - Eastern Basin	2	6.4	0	—	0.3× / 6.2
Quakes · North Pacific Ocean	2	6	0	—	0.2× / 8.4
Missiles · Indian Ocean	2	5.6	0	—	2.0× / 1
Derelicts · Philippine Sea	2	5	1	12	1.0× / 2
Derelicts · English Channel	2	4.1	0	—	3.3× / 0.6
Debris · South Pacific Ocean	2	4.1	1	29	5.0× / 0.4
Surveys · South Pacific Ocean	2	1.9	0	—	2.0× / 1
Incidents · Indian Ocean	2	0.2	0	—	0.2× / 9.2
Wrecks · Caribbean Sea	1	326.9	11	288	1.3× / 0.8
Wrecks · Arabian Sealong running	1	147.2	5	1,127	0.7× / 1.4
Exercises · South China Sea	1	92	0	—	0.4× / 2.6
Surveys · Indian Ocean	1	75.4	2	157	1.0× / 1
Exercises · Philippine Sea	1	55.7	0	—	0.3× / 3.8
Nav aids · Arabian Sea	1	44.9	2	114	0.6× / 1.8
Nav aids · Arafura Sea	1	41.7	2	311	5.0× / 0.2
Wrecks · North Pacific Ocean	1	40.4	2	179	5.0× / 0.2
Nav aids · Indian Oceanlong running	1	31.2	1	658	1.7× / 0.6
Surveys · Sea of Azov	1	26.2	1	26	new / 0
Surveys · Gulf of Guinea	1	23.3	1	23	5.0× / 0.2
Nav aids · Celtic Sea	1	18.3	1	18	1.0× / 1
Incidents · Malacca Strait	1	17.6	0	—	new / 0
Restricted · South Atlantic Ocean	1	14.8	0	—	new / 0
Surveys · Philippine Sea	1	14.5	0	—	new / 0
Restricted · Caribbean Sea	1	14.2	0	—	new / 0
Spills · Beaufort Sea	1	14	0	—	new / 0
Spills · Gulf of Alaska	1	14	0	—	2.5× / 0.4
Spills · North Pacific Ocean	1	14	0	—	0.7× / 1.4
Wrecks · Southern Ocean	1	13.4	1	13	new / 0
Cable ops · North Sea	1	12.4	1	12	0.4× / 2.6
Surveys · Celtic Sea	1	12.3	1	12	1.0× / 1
Other · North Pacific Ocean	1	12.3	1	12	1.0× / 1
Surveys · Bass Strait	1	11	0	—	new / 0
Spills · The Coastal Waters of Southeast Alaska and British Columbia	1	10	1	10	5.0× / 0.2
Cable ops · North Pacific Ocean	1	8.9	0	—	new / 0
Missiles · Barentsz Sea	1	8.2	0	—	0.3× / 3.6
Incidents · Bismarck Sea	1	8.1	0	—	5.0× / 0.2
Incidents · Tyrrhenian Sea	1	8	1	8	1.3× / 0.8
Incidents · Java Sea	1	7.9	0	—	1.7× / 0.6
Exercises · Barentsz Sea	1	7.3	0	—	2.5× / 0.4
Volcanic · Caribbean Sealong running	1	7	1	647	new / 0
Piracy · Gulf of Aden	1	7	0	—	1.3× / 0.8
Piracy · Makassar Strait	1	7	0	—	new / 0
Cable ops · Celtic Sea	1	6.7	0	—	1.3× / 0.8
Cable ops · Mediterranean Sea - Eastern Basin	1	6.4	0	—	0.4× / 2.4
Nav aids · Alboran Sea	1	6.2	1	6	new / 0
Other · Mediterranean Sea - Western Basin	1	6.1	1	6	new / 0
Quakes · North Atlantic Ocean	1	5.7	0	—	2.5× / 0.4
Missiles · Laccadive Sea	1	5.2	0	—	1.0× / 1
Cable ops · Gulf of Thailand	1	4.5	1	4	new / 0
Debris · Arafura Sea	1	3	0	—	new / 0
Debris · Caribbean Sea	1	3	0	—	5.0× / 0.2
Derelicts · Coral Sea	1	3	0	—	new / 0
Quakes · Coral Sea	1	3	0	—	0.2× / 5
Derelicts · Gulf of Mexico	1	3	0	—	1.0× / 1
Debris · Indian Ocean	1	3	0	—	1.7× / 0.6
Derelicts · Java Sea	1	3	0	—	new / 0
Debris · North Atlantic Ocean	1	3	0	—	0.6× / 1.6
Containers · North Sea	1	3	0	—	new / 0
Debris · North Sea	1	3	0	—	5.0× / 0.2
Debris · Norwegian Sea	1	3	0	—	new / 0
Debris · Persian Gulf	1	3	0	—	5.0× / 0.2
Quakes · South Atlantic Ocean	1	3	0	—	0.6× / 1.8
Derelicts · South Pacific Ocean	1	3	0	—	0.7× / 1.4
Nav aids · Bristol Channel	1	2.8	0	—	new / 0
Other · Indian Ocean	1	2.8	1	2	0.8× / 1.2
Cable ops · Eastern China Sea	1	2.4	1	111	1.3× / 0.8
Incidents · Celebes Sea	1	2.3	0	—	new / 0
Quakes · Celebes Sea	1	2.2	1	2	5.0× / 0.2
Missiles · South China Sea	1	2.1	0	—	new / 0
Derelicts · Timor Sea	1	1.8	1	1	5.0× / 0.2
Exercises · Bering Sea	1	1	0	—	0.8× / 1.2
Other · Gulf of Thailand	1	0.8	1	0	new / 0
Incidents · North Sea	1	0.5	0	—	new / 0
Nav aids · Strait of Gibraltar	1	0.3	0	—	new / 0
Incidents · Tasman Sea	1	0.2	0	—	0.7× / 1.4
Incidents · Eastern China Sea	1	0.1	0	—	5.0× / 0.2
Incidents · Solomon Sea	1	0.1	0	—	2.5× / 0.4
Wrecks · Coral Sea	1	0	0	—	new / 0
Nav aids · Caribbean Sealong running	0	462	11	1,175	0.0× / 0.2
Surveys · Arctic Oceanlong running	0	216.7	7	2,379	— / 0
Surveys · Beaufort Sealong running	0	139.6	4	2,454	— / 0
Other · Caribbean Sea	0	120	4	100	0.0× / 1
Surveys · Bering Sea	0	90	3	294	— / 0
Other · Coral Sealong running	0	90	3	746	0.0× / 0.4
Exercises · Ionian Sea	0	90	3	119	0.0× / 0.4
Nav aids · Tasman Sea	0	90	3	334	0.0× / 0.2
Cable ops · Persian Gulf	0	80.6	2	151	0.0× / 0.6
Other · South China Sealong running	0	77.7	2	886	0.0× / 1.2
Wrecks · South Pacific Ocean	0	77.7	2	100	— / 0
Ordnance · Black Sea	0	60	2	319	— / 0
Nav aids · Malacca Straitlong running	0	60	2	552	— / 0
Nav aids · Persian Gulf	0	60	2	270	0.0× / 0.4
Other · Sea of Azov	0	60	2	275	0.0× / 0.2
Surveys · The Northwestern Passageslong running	0	60	2	1,728	— / 0
Cable ops · Philippine Sea	0	46	1	270	0.0× / 0.4
Wrecks · Hudson Bay	0	36.7	1	131	— / 0
Nav aids · Gulf of California	0	36.6	1	221	— / 0
Surveys · Persian Gulflong running	0	30.6	1	412	0.0× / 0.4
Missiles · Aegean Sea	0	30	1	119	— / 0
Nav aids · Andaman or Burma Sea	0	30	1	55	0.0× / 0.6
Wrecks · Andaman or Burma Sea	0	30	1	114	— / 0
Restricted · Baltic Sea	0	30	1	227	— / 0
Nav aids · Bass Straitlong running	0	30	1	729	0.0× / 1.2
Restricted · Black Sealong running	0	30	1	1,425	0.0× / 0.6
Wrecks · Black Sea	0	30	1	199	— / 0
Cable ops · Caribbean Sea	0	30	1	135	0.0× / 0.2
Surveys · Chukchi Sea	0	30	1	234	— / 0
Nav aids · Great Australian Bightlong running	0	30	1	515	0.0× / 0.2
Wrecks · Gulf of Californialong running	0	30	1	550	— / 0
Incidents · Gulf of Guinea	0	30	1	81	0.0× / 0.2
Volcanic · Gulf of Guinea	0	30	1	51	— / 0
Cable ops · Gulf of Mexico	0	30	1	176	0.0× / 2.2
Wrecks · Gulf of Mexico	0	30	1	45	0.0× / 0.2
Wrecks · Gulf of Thailand	0	30	1	148	— / 0
Wrecks · Irish Sea and St. George's Channel	0	30	1	111	— / 0
Wrecks · Malacca Straitlong running	0	30	1	752	0.0× / 0.2
Nav aids · Mediterranean Sea - Eastern Basinlong running	0	30	1	384	0.0× / 0.6
Wrecks · North Atlantic Ocean	0	30	1	90	0.0× / 0.2
Restricted · Persian Gulf	0	30	1	34	0.0× / 0.2
Structures · Persian Gulf	0	30	1	238	— / 0

Cite: seahazards.com Sea Ledger, 2017-04, 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.