Sea Ledger, November 2020

2020-11-01 to 2020-11-30 · archive

issued: 763
warning-days in force: 9,401
in force at month end: 318
sea × type cells: 220

baseline: same month, previous 5 years (2019-11, 2018-11, 2017-11, 2016-11, 2015-11)

By type

type	issued	warning-days	in force at end
Exercises	208	1,861.9	64
Surveys	88	1,652.4	54
Icebergs	88	93.1	4
Incidents	85	725.2	28
Missiles	81	615.4	21
Nav aids	49	1,750.3	59
Cable ops	37	463.5	16
Quakes	25	72.8	4
Derelicts	22	102.4	4
Debris	19	53.4	1
Piracy	14	65.9	0
Wrecks	13	1,257.8	41
Spills	10	142	4
Other	9	259.8	9
Storms	9	14.1	0
Containers	5	14.7	1
Restricted	1	99.6	3
Volcanic	0	66.5	2
Structures	0	30	1
Ordnance	0	30	1
Mines	0	30	1

By sea and type · 200 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Icebergs · South Atlantic Ocean	30	30.1	1	30	1.2× / 24.4
Exercises · Black Seasurge	28	357	14	52	3.1× / 9
Icebergs · Southern Oceansurge	28	28	1	30	2.3× / 12
Exercises · North Pacific Ocean	25	218.7	5	66	1.1× / 22.6
Surveys · Aegean Seasurge	24	51.3	1	22	40× / 0.6
Icebergs · Davis Straitsurge	24	29.4	0	—	4.6× / 5.2
Exercises · Aegean Sea	23	220.8	10	336	2.0× / 11.6
Missiles · North Atlantic Oceansurge	22	80.6	4	31	3.7× / 6
Exercises · Mediterranean Sea - Eastern Basin	20	139.5	4	333	1.3× / 16
Incidents · South China Sea	19	210.5	6	295	0.7× / 27
Incidents · North Pacific Ocean	18	159.9	7	44	0.9× / 20.4
Surveys · South Atlantic Ocean	17	181.8	4	57	1.4× / 12.6
Exercises · South Atlantic Ocean	17	100.1	4	31	1.1× / 15.2
Exercises · South Pacific Oceansurge	16	96.5	2	34	3.0× / 5.4
Missiles · Barentsz Seasurge	16	73.2	3	28	2.7× / 6
Missiles · South Pacific Oceansurge	16	68.1	1	27	5.3× / 3
Exercises · Arabian Sea	14	86.2	3	33	1.8× / 7.6
Exercises · Bay of Bengal	12	81.3	3	32	0.9× / 12.6
Piracy · Gulf of Guineasurge	12	49.8	0	—	2.7× / 4.4
Cable ops · Aegean Seasurge	11	74.1	3	45	55× / 0.2
Quakes · South Pacific Ocean	10	29.5	1	31	0.7× / 15
Surveys · Mediterranean Sea - Eastern Basinsurge	9	181.4	5	157	3.0× / 3
Nav aids · South Pacific Oceansurgelong running	8	287.6	9	756	4.4× / 1.8
Surveys · Persian Gulfsurgelong running	8	170.9	5	552	2.4× / 3.4
Exercises · North Atlantic Ocean	8	59.6	4	55	1.6× / 5
Derelicts · North Atlantic Oceansurge	8	36	2	20	2.7× / 3
Debris · Timor Seasurge	8	21.8	1	27	3.6× / 2.2
Storms · Gulf of Mexiconew	8	13.6	0	—	new / 0
Nav aids · North Atlantic Oceanlong running	7	153.6	5	478	1.4× / 5.2
Exercises · Mediterranean Sea - Western Basinsurge	7	131.1	6	333	35× / 0.2
Exercises · Yellow Sea	7	51.6	2	38	0.8× / 8.6
Missiles · Indian Oceansurge	7	37	3	30	2.2× / 3.2
Missiles · Black Sea	6	233.6	4	33	1.1× / 5.4
Surveys · Arabian Sea	6	115.1	5	55	1.0× / 5.8
Nav aids · South Atlantic Ocean	6	87.7	4	93	0.7× / 8.4
Incidents · Coral Sea	6	32.1	0	—	1.8× / 3.4
Incidents · South Pacific Ocean	6	23.3	1	20	0.9× / 6.6
Incidents · Arabian Seasurge	6	23.1	3	21	3.0× / 2
Cable ops · Celtic Seasurge	6	11.4	0	—	15× / 0.4
Icebergs · Labrador Sea	6	5.6	2	5	0.3× / 20.8
Incidents · North Atlantic Ocean	5	64.5	2	32	0.3× / 15.4
Exercises · Gulf of Mexicosurge	5	43.5	0	—	2.8× / 1.8
Nav aids · Inner Seas off the West Coast of Scotland	5	37.5	1	354	1.3× / 3.8
Exercises · Japan Seasurge	5	30.3	1	28	8.3× / 0.6
Incidents · Black Seasurge	5	14.7	0	—	25× / 0.2
Derelicts · Bay of Bengal	5	13.7	1	10	1.9× / 2.6
Debris · Arafura Seasurge	5	13.3	0	—	8.3× / 0.6
Quakes · North Pacific Ocean	5	12.8	1	24	0.8× / 6.4
Surveys · North Atlantic Ocean	4	283.3	12	297	0.6× / 6.8
Nav aids · Caribbean Seasurge	4	162.9	6	89	2.2× / 1.8
Spills · Gulf of Mexico	4	75	1	40	0.8× / 4.8
Nav aids · North Sea	4	65.7	2	64	0.3× / 13.2
Spills · North Atlantic Ocean	4	54	1	43	1.5× / 2.6
Incidents · Laccadive Sea	4	52.4	2	24	1.5× / 2.6
Missiles · Japan Seasurge	4	29.6	2	32	10× / 0.4
Surveys · Bay of Bengal	4	29.5	1	35	1.2× / 3.4
Exercises · Caribbean Seasurge	4	28.2	0	—	5.0× / 0.8
Wrecks · English Channelsurge	4	26.9	2	18	10× / 0.4
Surveys · South Pacific Oceansurgelong running	3	55.8	3	425	3.0× / 1
Exercises · Barentsz Seasurge	3	46.9	2	159	3.8× / 0.8
Surveys · English Channelnew	3	39.3	1	26	new / 0
Nav aids · Irish Sea and St. George's Channelsurge	3	30.2	0	—	2.1× / 1.4
Cable ops · North Atlantic Ocean	3	25.6	0	—	0.9× / 3.4
Missiles · North Pacific Ocean	3	17.1	0	—	0.5× / 5.6
Nav aids · English Channel	3	12.4	1	28	0.7× / 4.2
Incidents · Philippine Sea	3	11.3	2	12	0.8× / 3.8
Debris · Indian Oceansurge	3	9	0	—	15× / 0.2
Quakes · Indian Ocean	3	9	0	—	1.5× / 2
Containers · North Atlantic Oceansurge	3	9	0	—	7.5× / 0.4
Derelicts · South Pacific Ocean	3	9	0	—	1.5× / 2
Other · The Coastal Waters of Southeast Alaska and British Columbianew	3	4.5	0	—	new / 0
Exercises · South China Sea	3	4	0	—	1.1× / 2.6
Wrecks · Persian Gulflong running	2	260.7	9	516	10× / 0.2
Nav aids · North Pacific Oceanlong running	2	181.5	6	486	0.5× / 3.8
Wrecks · Arabian Sealong running	2	82.7	2	433	10× / 0.2
Surveys · Mediterranean Sea - Western Basinnew	2	77.5	3	159	new / 0
Wrecks · Inner Seas off the West Coast of Scotlandnew	2	61.9	2	52	new / 0
Cable ops · South China Sea	2	57.8	2	47	1.4× / 1.4
Exercises · Laccadive Sea	2	32.9	1	32	0.7× / 3
Cable ops · South Atlantic Ocean	2	30.5	2	61	0.9× / 2.2
Cable ops · Andaman or Burma Sea	2	23.1	2	11	10× / 0.2
Cable ops · Arabian Sea	2	22.4	0	—	2.5× / 0.8
Exercises · Andaman or Burma Sea	2	19.5	0	—	3.3× / 0.6
Missiles · Greenland Sea	2	19.1	1	18	2.5× / 0.8
Cable ops · Philippine Sea	2	18.7	0	—	1.7× / 1.2
Exercises · Gulf of Californianew	2	16.2	0	—	new / 0
Quakes · Southern Ocean	2	6	0	—	10× / 0.2
Debris · Arabian Seanew	2	4.4	0	—	new / 0
Exercises · Philippine Sea	2	1.9	0	—	0.4× / 4.6
Incidents · South Atlantic Ocean	2	1.2	1	26	0.3× / 6.4
Nav aids · Coral Sea	2	0.9	1	8	0.6× / 3.2
Incidents · Timor Sea	2	0.1	0	—	2.0× / 1
Surveys · Black Sea	1	129.5	4	166	0.7× / 1.4
Nav aids · Laccadive Sealong running	1	88.5	3	577	1.7× / 0.6
Nav aids · Gulf of Mexico	1	69.7	2	68	0.6× / 1.8
Restricted · South Atlantic Ocean	1	69.6	2	333	2.5× / 0.4
Wrecks · South Pacific Ocean	1	62.9	2	305	new / 0
Wrecks · Caribbean Sea	1	61	2	242	1.0× / 1
Cable ops · North Pacific Ocean	1	44.4	2	90	1.3× / 0.8
Other · Persian Gulf	1	37.4	2	147	new / 0
Cable ops · Persian Gulf	1	30	1	77	5.0× / 0.2
Surveys · Sea of Marmara	1	30	1	84	2.5× / 0.4
Nav aids · Bass Strait	1	25	1	24	0.4× / 2.4
Cable ops · Mediterranean Sea - Eastern Basin	1	23	0	—	1.0× / 1
Other · South Atlantic Ocean	1	22.8	1	42	0.6× / 1.6
Incidents · Caribbean Sea	1	19.2	1	36	0.2× / 5.2
Wrecks · Kara Sea	1	18.2	1	18	new / 0
Cable ops · Caribbean Sea	1	17.4	1	41	1.7× / 0.6
Incidents · Mediterranean Sea - Eastern Basin	1	17.2	0	—	0.1× / 11.8
Incidents · Andaman or Burma Sea	1	16.9	0	—	new / 0
Incidents · Malacca Strait	1	12.8	0	—	2.5× / 0.4
Cable ops · South Pacific Ocean	1	12.2	0	—	0.6× / 1.6
Incidents · Japan Sea	1	11.4	1	11	0.6× / 1.6
Surveys · Japan Sea	1	9.5	0	—	5.0× / 0.2
Piracy · Singapore Strait	1	9.1	0	—	5.0× / 0.2
Surveys · Gulf of Mexico	1	9	0	—	2.5× / 0.4
Missiles · South Atlantic Ocean	1	9	0	—	5.0× / 0.2
Surveys · Ligurian Sea	1	7.2	0	—	new / 0
Piracy · Mozambique Channel	1	7	0	—	new / 0
Missiles · Labrador Sea	1	6.6	1	6	new / 0
Cable ops · Laccadive Sea	1	6.5	1	6	new / 0
Cable ops · North Sea	1	6.4	0	—	0.8× / 1.2
Surveys · Caribbean Sea	1	5.9	1	5	1.0× / 1
Nav aids · Timor Sea	1	5.9	0	—	new / 0
Incidents · Gulf of Thailand	1	5.8	1	5	0.5× / 2.2
Other · North Atlantic Ocean	1	5.7	0	—	1.0× / 1
Missiles · Philippine Sea	1	5.3	0	—	5.0× / 0.2
Missiles · Laccadive Sea	1	4.9	0	—	1.3× / 0.8
Spills · Caribbean Sea	1	4	1	4	new / 0
Other · Gulf of Guinea	1	4	0	—	new / 0
Surveys · Indian Ocean	1	3.7	0	—	0.5× / 2.2
Containers · North Sea	1	3.7	0	—	5.0× / 0.2
Exercises · Tyrrhenian Sea	1	3.7	0	—	new / 0
Nav aids · Celtic Sea	1	3.1	1	3	0.6× / 1.6
Quakes · Banda Sea	1	3	0	—	1.0× / 1
Derelicts · Caribbean Sea	1	3	0	—	0.6× / 1.8
Derelicts · Laccadive Sea	1	3	0	—	1.0× / 1
Derelicts · Mediterranean Sea - Eastern Basin	1	3	0	—	2.5× / 0.4
Debris · Persian Gulf	1	3	0	—	new / 0
Quakes · Philippine Sea	1	3	0	—	0.8× / 1.2
Quakes · Solomon Sea	1	3	0	—	1.7× / 0.6
Derelicts · South China Sea	1	3	0	—	1.3× / 0.8
Exercises · Coral Sea	1	2.4	0	—	0.8× / 1.2
Quakes · Coral Sea	1	1.6	1	1	0.6× / 1.6
Containers · North Pacific Ocean	1	1.4	1	31	5.0× / 0.2
Missiles · Arctic Ocean	1	1.3	1	1	1.3× / 0.8
Spills · Chukchi Sea	1	1	1	1	new / 0
Derelicts · Inner Seas off the West Coast of Scotland	1	0.8	0	—	new / 0
Other · Celtic Sea	1	0.6	0	—	5.0× / 0.2
Storms · North Atlantic Ocean	1	0.5	0	—	2.5× / 0.4
Incidents · Tasman Sea	1	0.4	0	—	0.8× / 1.2
Derelicts · English Channel	1	0.3	0	—	1.3× / 0.8
Surveys · Mozambique Channel	1	0.3	1	0	new / 0
Other · Bering Sea	1	0.2	0	—	5.0× / 0.2
Incidents · Indian Ocean	1	0.2	0	—	0.3× / 4
Incidents · Bass Strait	1	0.1	0	—	5.0× / 0.2
Quakes · Japan Sea	1	0	1	0	5.0× / 0.2
Exercises · Ligurian Sea	1	0	0	—	new / 0
Wrecks · South China Sealong running	0	270	9	652	0.0× / 2.2
Wrecks · North Atlantic Oceanlong running	0	120	4	679	0.0× / 1
Wrecks · South Atlantic Ocean	0	113.5	2	126	— / 0
Exercises · Ionian Sea	0	90	3	336	— / 0
Nav aids · Mediterranean Sea - Western Basin	0	90	3	183	0.0× / 0.6
Surveys · Sea of Okhotsk	0	62	2	238	0.0× / 0.6
Nav aids · Arabian Sealong running	0	60	2	389	0.0× / 1.6
Surveys · Arctic Ocean	0	60	2	42	0.0× / 0.6
Nav aids · Bay of Bengal	0	60	2	173	0.0× / 1
Nav aids · Gulf of California	0	60	2	68	0.0× / 0.2
Other · South Pacific Ocean	0	60	2	256	0.0× / 0.4
Nav aids · Persian Gulf	0	52.6	1	229	0.0× / 0.2
Nav aids · Andaman or Burma Sealong running	0	31.5	1	550	0.0× / 0.6
Missiles · Aegean Sea	0	30	1	177	0.0× / 1.2
Nav aids · Alboran Sea	0	30	1	67	— / 0
Derelicts · Arabian Sea	0	30	1	311	0.0× / 0.6
Other · Arabian Sealong running	0	30	1	584	0.0× / 0.4
Surveys · Barentsz Sea	0	30	1	42	0.0× / 1.4
Wrecks · Bay of Bengal	0	30	1	36	0.0× / 0.2
Surveys · Bering Sea	0	30	1	40	— / 0
Cable ops · Black Sea	0	30	1	82	— / 0
Volcanic · Caribbean Sea	0	30	1	168	— / 0
Mines · English Channel	0	30	1	38	0.0× / 0.4
Wrecks · Gulf of California	0	30	1	53	— / 0
Nav aids · Gulf of Thailandlong running	0	30	1	410	— / 0
Nav aids · Hudson Strait	0	30	1	66	— / 0
Incidents · Java Sea	0	30	1	266	0.0× / 1.6
Nav aids · Mediterranean Sea - Eastern Basin	0	30	1	116	0.0× / 0.6
Other · Mediterranean Sea - Eastern Basin	0	30	1	67	0.0× / 0.8
Cable ops · Mediterranean Sea - Western Basin	0	30	1	33	0.0× / 0.6
Nav aids · Mozambique Channel	0	30	1	47	0.0× / 0.6
Volcanic · Mozambique Channellong running	0	30	1	424	— / 0
Wrecks · Mozambique Channel	0	30	1	47	— / 0
Other · North Pacific Ocean	0	30	1	118	0.0× / 6.6
Wrecks · North Pacific Oceanlong running	0	30	1	606	0.0× / 0.6
Ordnance · North Sealong running	0	30	1	413	0.0× / 1
Other · North Sea	0	30	1	33	0.0× / 0.6
Nav aids · Norwegian Sea	0	30	1	108	— / 0
Restricted · Persian Gulflong running	0	30	1	593	— / 0
Wrecks · Red Sea	0	30	1	352	— / 0
Wrecks · Sea of Okhotsk	0	30	1	88	— / 0
Structures · South China Sealong running	0	30	1	371	0.0× / 0.2

Cite: seahazards.com Sea Ledger, 2020-11, 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.