Sea Ledger, April 2018

2018-04-01 to 2018-04-30 · archive

issued: 623
warning-days in force: 13,227
in force at month end: 437
sea × type cells: 261

baseline: same month, previous 5 years (2017-04, 2016-04, 2015-04, 2014-04, 2013-04)

By type

type	issued	warning-days	in force at end
Incidents	155	1,456.8	52
Exercises	92	1,177.5	33
Icebergs	92	101.7	4
Nav aids	70	3,693	126
Surveys	42	2,142.5	71
Missiles	33	236.2	5
Cable ops	26	302.4	10
Derelicts	25	143	4
Quakes	25	72.9	2
Other	16	519.8	16
Spills	14	194	7
Debris	8	21.8	1
Piracy	7	50.5	0
Wrecks	7	2,448.1	84
Ordnance	5	175.9	6
Restricted	4	169.2	5
Structures	1	63.4	2
Storms	1	77.8	3
Volcanic	0	180	6
Containers	0	0.1	0

By sea and type · 200 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Incidents · South China Seasurge	34	252.4	7	41	2.1× / 15.8
Incidents · North Pacific Ocean	32	266.9	10	248	1.2× / 26.6
Icebergs · South Atlantic Oceansurge	31	33.2	1	30	7.8× / 4
Icebergs · Southern Oceansurge	29	28	1	30	4.1× / 7
Incidents · Mediterranean Sea - Eastern Basin	24	312.9	16	34	1.4× / 17.2
Icebergs · Labrador Sea	21	24.1	2	29	1.8× / 11.4
Exercises · North Pacific Ocean	17	175.7	5	63	1.0× / 16.8
Nav aids · South Atlantic Ocean	14	480	18	167	1.8× / 7.8
Nav aids · Coral Sealong running	11	187	6	751	1.8× / 6
Surveys · Arabian Seasurge	10	169.8	6	89	2.9× / 3.4
Exercises · Bay of Bengal	10	85.3	4	41	1.1× / 8.8
Exercises · Arabian Sea	10	70.5	1	31	1.7× / 6
Quakes · South Pacific Ocean	10	27.2	1	28	0.8× / 12.8
Incidents · South Pacific Ocean	9	61.3	2	43	1.1× / 8.4
Cable ops · North Atlantic Ocean	9	44	1	59	2.0× / 4.6
Surveys · South Atlantic Ocean	8	280.6	7	76	0.7× / 11.2
Nav aids · North Sea	8	165.3	6	299	0.8× / 10.2
Incidents · North Atlantic Ocean	8	128.7	4	43	0.5× / 17
Incidents · Philippine Seasurge	8	74.8	3	77	2.2× / 3.6
Exercises · Mediterranean Sea - Eastern Basin	8	62.3	2	62	1.8× / 4.4
Icebergs · North Atlantic Ocean	8	10.4	0	—	0.5× / 17.4
Nav aids · North Pacific Oceansurge	7	282.8	12	184	8.8× / 0.8
Exercises · Black Sea	7	152	2	62	0.6× / 11.6
Exercises · South Atlantic Ocean	7	32.4	0	—	1.5× / 4.8
Spills · Gulf of Mexico	6	98	3	41	1.3× / 4.8
Missiles · Barentsz Sea	6	55.6	0	—	1.7× / 3.6
Missiles · Japan Seasurge	6	28.2	1	33	4.3× / 1.4
Surveys · North Atlantic Oceanlong running	5	301	11	802	1.3× / 3.8
Ordnance · North Seasurge	5	113.3	4	61	5.0× / 1
Incidents · Gulf of Thailandsurge	5	36.1	2	27	13× / 0.4
Exercises · South Pacific Ocean	5	27.2	0	—	0.9× / 5.8
Missiles · North Atlantic Ocean	5	22.8	1	33	0.8× / 6.6
Exercises · South China Seasurge	5	17.5	0	—	2.3× / 2.2
Incidents · Coral Sea	5	10.3	0	—	1.1× / 4.6
Exercises · Aegean Seasurge	4	308.5	10	124	2.5× / 1.6
Nav aids · North Atlantic Oceanlong running	4	233.3	8	430	0.7× / 6.2
Exercises · North Atlantic Ocean	4	70.6	3	124	1.0× / 4
Nav aids · English Channel	4	35.4	2	62	1.8× / 2.2
Spills · North Atlantic Oceansurge	4	27	3	44	2.5× / 1.6
Piracy · Gulf of Guinea	4	23.2	0	—	0.9× / 4.4
Incidents · Indian Ocean	4	21.6	0	—	0.5× / 8.8
Derelicts · South Atlantic Oceansurge	4	18.3	0	—	4.0× / 1
Exercises · Yellow Sea	4	17.2	1	24	0.4× / 10.8
Derelicts · Indian Ocean	4	15.7	1	28	0.7× / 5.6
Quakes · North Pacific Ocean	4	12	0	—	0.6× / 6.4
Surveys · Indian Oceansurgelong running	3	117.4	4	522	3.0× / 1
Nav aids · Inner Seas off the West Coast of Scotland	3	107	4	224	0.8× / 3.8
Surveys · Mediterranean Sea - Eastern Basin	3	64	2	88	1.4× / 2.2
Incidents · Caribbean Sea	3	54.7	0	—	0.8× / 3.8
Incidents · Eastern China Seasurge	3	45.5	1	30	15× / 0.2
Incidents · South Atlantic Ocean	3	39.9	1	39	0.4× / 7.8
Derelicts · South Pacific Oceansurge	3	37.6	1	61	2.1× / 1.4
Missiles · South China Seasurge	3	17.7	0	—	15× / 0.2
Missiles · South Pacific Ocean	3	13.6	0	—	1.3× / 2.4
Derelicts · Mediterranean Sea - Eastern Basinsurge	3	9	0	—	5.0× / 0.6
Derelicts · North Atlantic Ocean	3	8.7	1	29	1.4× / 2.2
Quakes · Indian Ocean	3	7.1	1	11	1.4× / 2.2
Wrecks · North Sealong running	2	210	7	397	1.4× / 1.4
Nav aids · Tasman Sealong running	2	96.7	3	426	10× / 0.2
Spills · North Pacific Ocean	2	48	0	—	1.4× / 1.4
Cable ops · South Atlantic Ocean	2	44.2	0	—	0.2× / 9.8
Missiles · North Pacific Ocean	2	37.9	2	45	0.4× / 5.6
Other · Arabian Seanew	2	25.9	1	22	new / 0
Nav aids · Irish Sea and St. George's Channel	2	25.1	1	24	1.0× / 2
Cable ops · South Pacific Ocean	2	16.5	1	16	10× / 0.2
Cable ops · Arabian Sea	2	15.3	0	—	0.7× / 2.8
Nav aids · Andaman or Burma Sea	2	14.9	0	—	3.3× / 0.6
Other · Tasman Sea	2	11.5	0	—	10× / 0.2
Restricted · Inner Seas off the West Coast of Scotlandnew	2	11	0	—	new / 0
Exercises · Gulf of Mexico	2	10.9	0	—	1.0× / 2
Surveys · North Sea	2	10.9	1	13	2.0× / 1
Surveys · Bay of Biscaynew	2	10.8	0	—	new / 0
Missiles · Laccadive Sea	2	10.7	0	—	2.0× / 1
Cable ops · Philippine Sea	2	10.5	0	—	5.0× / 0.4
Cable ops · Mediterranean Sea - Eastern Basin	2	9.6	0	—	0.8× / 2.6
Surveys · Mediterranean Sea - Western Basin	2	7	2	6	3.3× / 0.6
Quakes · Molukka Sea	2	6	0	—	5.0× / 0.4
Derelicts · North Pacific Ocean	2	6	0	—	1.4× / 1.4
Debris · English Channel	2	5.5	1	22	10× / 0.2
Missiles · South Atlantic Ocean	2	4.7	0	—	1.7× / 1.2
Incidents · Bismarck Sea	2	3.8	0	—	5.0× / 0.4
Missiles · Arabian Sea	2	3.3	0	—	5.0× / 0.4
Debris · Coral Seanew	2	3	0	—	new / 0
Icebergs · Gulf of St. Lawrencenew	2	3	0	—	new / 0
Nav aids · The Coastal Waters of Southeast Alaska and British Columbia	2	0.8	0	—	3.3× / 0.6
Incidents · Tasman Sea	2	0.7	0	—	1.7× / 1.2
Incidents · Davis Strait	2	0.2	0	—	2.0× / 1
Nav aids · Caribbean Sea	1	625.7	20	342	5.0× / 0.2
Wrecks · South Pacific Ocean	1	149.1	5	217	new / 0
Other · Caribbean Sealong running	1	134.6	4	465	1.0× / 1
Nav aids · Bay of Bengallong running	1	106.5	3	381	1.0× / 1
Wrecks · North Pacific Oceanlong running	1	100.6	4	375	2.5× / 0.4
Wrecks · North Atlantic Oceanlong running	1	94.2	4	455	5.0× / 0.2
Nav aids · Mediterranean Sea - Western Basin	1	87.4	3	75	2.5× / 0.4
Wrecks · Laccadive Sea	1	70.4	3	325	new / 0
Nav aids · Gulf of California	1	65.4	3	184	new / 0
Nav aids · Indian Ocean	1	64	2	254	1.3× / 0.8
Nav aids · Laccadive Sea	1	61	2	209	0.7× / 1.4
Surveys · Persian Gulf	1	60.3	3	130	2.5× / 0.4
Surveys · Barentsz Sea	1	56.7	2	34	new / 0
Surveys · Bay of Bengallong running	1	43.3	1	661	0.4× / 2.4
Wrecks · Indian Ocean	1	41.4	2	298	5.0× / 0.2
Surveys · South Pacific Ocean	1	37.8	0	—	0.7× / 1.4
Derelicts · South China Sealong running	1	32.7	1	465	0.8× / 1.2
Cable ops · Indian Ocean	1	30	1	41	2.5× / 0.4
Exercises · Laccadive Sea	1	30	1	33	0.6× / 1.8
Cable ops · Mediterranean Sea - Western Basin	1	19.6	1	68	1.3× / 0.8
Incidents · Balearic (Iberian Sea)	1	18.1	0	—	new / 0
Storms · South Pacific Ocean	1	17.8	1	17	new / 0
Cable ops · Java Sea	1	17.5	1	55	new / 0
Cable ops · North Sea	1	17.2	1	17	0.4× / 2.6
Incidents · Ionian Sea	1	16.5	1	16	5.0× / 0.2
Incidents · Mediterranean Sea - Western Basin	1	16.4	0	—	2.5× / 0.4
Other · Bay of Biscay	1	14	1	14	new / 0
Spills · Makassar Strait	1	14	0	—	new / 0
Incidents · Arabian Sea	1	13.9	0	—	0.4× / 2.4
Other · Timor Sea	1	12.6	1	12	2.5× / 0.4
Exercises · Philippine Sea	1	7.5	0	—	0.3× / 3.6
Restricted · South Pacific Ocean	1	7.3	0	—	new / 0
Piracy · Bay of Bengal	1	7	0	—	new / 0
Spills · Bering Sea	1	7	1	7	5.0× / 0.2
Piracy · Makassar Strait	1	7	0	—	5.0× / 0.2
Piracy · North Atlantic Ocean	1	7	0	—	new / 0
Missiles · Baffin Bay	1	6.5	0	—	1.3× / 0.8
Other · Japan Sea	1	6.4	0	—	new / 0
Incidents · Gulf of Mexico	1	6.1	1	6	0.2× / 5
Cable ops · Irish Sea and St. George's Channel	1	5.8	0	—	1.7× / 0.6
Nav aids · Norwegian Sea	1	5.7	0	—	new / 0
Surveys · Aegean Sea	1	5.5	1	5	0.7× / 1.4
Missiles · Bay of Bengal	1	5.2	0	—	0.7× / 1.4
Exercises · Red Sea	1	5	0	—	5.0× / 0.2
Other · Tyrrhenian Sea	1	5	0	—	new / 0
Surveys · Norwegian Sea	1	4.4	1	4	0.8× / 1.2
Incidents · Banda Sea	1	4.3	1	4	new / 0
Other · Barentsz Sea	1	4.3	0	—	new / 0
Exercises · Sea of Azov	1	4.2	0	—	new / 0
Debris · South Pacific Ocean	1	3.9	0	—	2.5× / 0.4
Exercises · Indian Ocean	1	3.7	1	33	0.6× / 1.8
Incidents · Alboran Sea	1	3.5	1	3	5.0× / 0.2
Debris · North Pacific Ocean	1	3.4	0	—	5.0× / 0.2
Structures · South Atlantic Ocean	1	3.4	0	—	new / 0
Incidents · Bay of Bengal	1	3.1	1	3	2.5× / 0.4
Derelicts · Adriatic Sea	1	3	0	—	new / 0
Quakes · Banda Sea	1	3	0	—	1.7× / 0.6
Derelicts · Caribbean Sea	1	3	0	—	1.0× / 1
Quakes · Ceram Sea	1	3	0	—	new / 0
Quakes · Japan Sea	1	3	0	—	2.5× / 0.4
Icebergs · Kara Sea	1	3	0	—	new / 0
Derelicts · Laccadive Sea	1	3	0	—	1.3× / 0.8
Incidents · Laccadive Sea	1	3	0	—	1.7× / 0.6
Surveys · Laccadive Sea	1	3	0	—	5.0× / 0.2
Debris · Mediterranean Sea - Eastern Basin	1	3	0	—	2.5× / 0.4
Derelicts · Mediterranean Sea - Western Basin	1	3	0	—	new / 0
Debris · North Atlantic Ocean	1	3	0	—	0.6× / 1.8
Quakes · Persian Gulf	1	3	0	—	5.0× / 0.2
Other · Persian Gulf	1	3	0	—	5.0× / 0.2
Quakes · Philippine Sea	1	3	0	—	0.3× / 3.2
Quakes · South Atlantic Ocean	1	3	0	—	0.8× / 1.2
Derelicts · Tasman Sea	1	3	0	—	5.0× / 0.2
Incidents · Bali Sea	1	2.8	1	2	new / 0
Exercises · Coral Sea	1	2.4	0	—	0.8× / 1.2
Nav aids · Timor Sea	1	2.3	0	—	new / 0
Exercises · Baltic Sea	1	2.2	0	—	0.4× / 2.8
Nav aids · Celtic Sea	1	2.2	0	—	1.0× / 1
Cable ops · South China Sea	1	2	1	2	0.3× / 3
Exercises · Mediterranean Sea - Western Basin	1	1.4	0	—	5.0× / 0.2
Other · North Pacific Ocean	1	1.3	0	—	1.3× / 0.8
Cable ops · Celtic Sea	1	1.2	1	1	1.3× / 0.8
Other · Aegean Sea	1	1	0	—	new / 0
Exercises · Celtic Sea	1	1	0	—	new / 0
Restricted · Tasman Sea	1	0.9	0	—	new / 0
Nav aids · Aegean Sea	1	0.5	0	—	new / 0
Other · South Atlantic Ocean	1	0.3	0	—	2.5× / 0.4
Nav aids · Strait of Gibraltar	1	0.2	0	—	5.0× / 0.2
Other · South Pacific Ocean	1	0.1	0	—	5.0× / 0.2
Incidents · Bass Strait	1	0	0	—	new / 0
Other · Gulf of Mexico	1	0	0	—	new / 0
Wrecks · Caribbean Sealong running	0	600	20	469	0.0× / 0.8
Wrecks · South China Sealong running	0	480	16	1,449	0.0× / 1
Nav aids · Gulf of Mexicolong running	0	216	7	451	0.0× / 2.4
Nav aids · South Pacific Ocean	0	182.2	6	319	0.0× / 2.6
Surveys · Arctic Oceanlong running	0	180	6	1,378	— / 0
Surveys · Beaufort Sealong running	0	150	5	2,039	— / 0
Surveys · The Northwestern Passageslong running	0	150	5	2,093	— / 0
Nav aids · Arabian Sealong running	0	104	2	368	0.0× / 1.8
Wrecks · Arabian Sealong running	0	90	3	557	0.0× / 0.8
Surveys · Bering Sea	0	90	3	293	— / 0
Other · Coral Sealong running	0	90	3	510	0.0× / 0.2
Wrecks · English Channel	0	90	3	60	0.0× / 0.2
Wrecks · Gulf of Mexicolong running	0	90	3	410	0.0× / 0.2
Exercises · Ionian Sea	0	90	3	124	0.0× / 0.4
Volcanic · Philippine Sealong running	0	90	3	2,192	0.0× / 0.6
Nav aids · South China Sea	0	90	3	166	— / 0
Other · South China Sealong running	0	65.4	2	1,251	0.0× / 1.2
Restricted · Black Sealong running	0	60	2	1,790	0.0× / 0.6
Storms · Caribbean Sea	0	60	2	230	— / 0
Surveys · Caribbean Sealong running	0	60	2	473	0.0× / 1.4
Volcanic · Caribbean Sea	0	60	2	48	0.0× / 0.2
Nav aids · Malacca Straitlong running	0	60	2	917	— / 0
Nav aids · Mediterranean Sea - Eastern Basinlong running	0	60	2	749	0.0× / 0.6

Cite: seahazards.com Sea Ledger, 2018-04, 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.