Sea Ledger, August 2021

2021-08-01 to 2021-08-31 · archive

issued: 687
warning-days in force: 11,252
in force at month end: 371
sea × type cells: 235

baseline: same month, previous 5 years (2020-08, 2019-08, 2018-08, 2017-08, 2016-08)

By type

type	issued	warning-days	in force at end
Exercises	144	1,337.5	55
Surveys	80	2,203.8	77
Quakes	75	214	3
Incidents	70	620.9	18
Icebergs	68	77.6	4
Nav aids	58	3,240.1	98
Cable ops	40	543.8	16
Missiles	35	286.2	4
Storms	21	24.3	1
Towing	20	25.6	1
Derelicts	19	144.9	4
Spills	19	213	11
Other	12	327.5	12
Wrecks	7	1,443.2	49
Debris	6	18	0
Restricted	4	129.9	4
Volcanic	4	204.8	7
Mines	3	55.4	1
Ordnance	2	72.7	4
Structures	0	62	2
Piracy	0	5.7	0
Containers	0	1.2	0

By sea and type · 200 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Quakes · South Atlantic Oceansurge	35	101.4	2	28	9.7× / 3.6
Icebergs · Labrador Sea	31	36.2	2	32	1.4× / 21.4
Exercises · North Pacific Ocean	30	347.8	14	110	1.4× / 21.4
Icebergs · Southern Ocean	30	30.1	1	31	1.5× / 19.8
Exercises · South Pacific Oceansurge	21	110.6	2	35	3.9× / 5.4
Surveys · South Atlantic Ocean	20	191	6	86	1.6× / 12.8
Towing · North Pacific Oceannew	20	25.6	1	25	new / 0
Incidents · North Pacific Ocean	15	172	5	43	0.7× / 22.4
Exercises · Black Sea	14	82	9	50	0.7× / 19.2
Storms · Gulf of Mexicosurge	13	14.2	1	18	4.6× / 2.8
Exercises · Arabian Seasurge	11	72.2	2	34	2.3× / 4.8
Missiles · North Atlantic Ocean	11	62.2	0	—	1.2× / 9.2
Cable ops · North Atlantic Ocean	10	192.8	4	66	1.6× / 6.4
Nav aids · North Sea	10	164.7	5	210	1.1× / 8.8
Incidents · South China Sealong running	10	102.1	3	512	0.3× / 34
Cable ops · North Pacific Oceansurge	10	97.2	2	166	13× / 0.8
Exercises · Mediterranean Sea - Eastern Basin	9	64.1	6	74	0.5× / 17.6
Exercises · Bay of Bengal	9	53	1	31	1.1× / 8.2
Quakes · South Pacific Ocean	9	26.6	1	33	1.0× / 9.4
Nav aids · South Atlantic Ocean	8	233.5	5	204	1.2× / 6.6
Missiles · Barentsz Seasurge	8	50.5	1	28	2.4× / 3.4
Incidents · Laccadive Seasurge	8	44.1	2	26	4.4× / 1.8
Cable ops · Celtic Seasurge	8	34.4	1	31	8.0× / 1
Incidents · South Pacific Ocean	8	25.7	2	28	1.1× / 7.2
Quakes · Southern Oceansurge	8	24	0	—	5.7× / 1.4
Exercises · Indian Oceansurge	8	20.1	3	25	4.0× / 2
Surveys · Persian Gulf	7	122.2	4	225	1.8× / 4
Exercises · South Atlantic Ocean	7	66.8	3	48	0.8× / 9
Surveys · Caribbean Seasurge	7	64.2	3	27	5.8× / 1.2
Exercises · North Atlantic Ocean	7	34.9	1	30	0.7× / 9.4
Incidents · South Atlantic Ocean	6	49.5	2	42	1.1× / 5.4
Missiles · Indian Oceansurge	6	17.3	0	—	4.3× / 1.4
Surveys · North Atlantic Ocean	5	591.5	18	243	0.7× / 7
Spills · North Pacific Ocean	5	53	3	44	1.7× / 3
Nav aids · English Channelsurge	5	44.9	2	41	2.8× / 1.8
Cable ops · Hudson Baynew	5	31.9	1	29	new / 0
Nav aids · The Northwestern Passagessurge	5	16.1	0	—	3.1× / 1.6
Quakes · Philippine Seasurge	5	12.1	0	—	3.6× / 1.4
Icebergs · South Atlantic Ocean	5	5.7	0	—	0.2× / 25.4
Storms · North Atlantic Ocean	5	4.8	0	—	1.1× / 4.4
Volcanic · Philippine Seasurge	4	142.8	5	256	20× / 0.2
Spills · North Atlantic Ocean	4	46	3	28	1.4× / 2.8
Exercises · Japan Seasurge	4	37.8	0	—	5.0× / 0.8
Exercises · Andaman or Burma Sea	4	16	0	—	1.7× / 2.4
Derelicts · North Atlantic Ocean	4	12	0	—	0.9× / 4.2
Exercises · Philippine Sea	4	8.5	0	—	0.7× / 6.2
Quakes · Caribbean Seasurge	4	6	0	—	4.0× / 1
Nav aids · North Atlantic Oceanlong running	3	355	11	752	0.5× / 6.4
Nav aids · Mediterranean Sea - Western Basinsurgelong running	3	154.1	5	457	3.8× / 0.8
Surveys · Norwegian Seasurge	3	110.7	3	80	3.0× / 1
Surveys · Sea of Okhotsk	3	107.2	4	74	1.9× / 1.6
Surveys · South Pacific Oceansurgelong running	3	99.9	3	699	3.8× / 0.8
Nav aids · Great Australian Bight	3	57.4	2	76	1.7× / 1.8
Surveys · Black Seasurge	3	55.4	2	174	2.1× / 1.4
Incidents · Philippine Sea	3	41.8	0	—	0.6× / 4.8
Surveys · Mediterranean Sea - Eastern Basin	3	39.9	3	27	0.8× / 4
Spills · Gulf of Mexico	3	37	1	41	0.4× / 7.6
Exercises · Bay of Biscaynew	3	21.6	0	—	new / 0
Incidents · Arafura Seasurge	3	15.4	0	—	7.5× / 0.4
Exercises · Mediterranean Sea - Western Basinsurge	3	14.6	0	—	2.1× / 1.4
Derelicts · North Pacific Oceansurge	3	13.9	1	16	2.1× / 1.4
Quakes · Andaman or Burma Seanew	3	9	0	—	new / 0
Quakes · North Pacific Ocean	3	9	0	—	0.5× / 5.6
Derelicts · South Pacific Oceansurge	3	9	0	—	2.1× / 1.4
Incidents · Indian Ocean	3	7.1	1	32	0.5× / 5.8
Incidents · Coral Sea	3	0.3	0	—	0.6× / 5.2
Nav aids · Gulf of Mexico	2	186.5	8	269	0.7× / 3
Surveys · Kara Sea	2	126.9	4	48	1.1× / 1.8
Nav aids · Indian Ocean	2	91.4	3	143	0.5× / 4.2
Nav aids · Laccadive Sea	2	72.1	2	40	2.5× / 0.8
Surveys · North Sea	2	69.7	3	71	0.4× / 4.6
Missiles · North Pacific Ocean	2	51.5	2	77	0.3× / 6.6
Surveys · Gulf of Mexico	2	51.1	2	31	3.3× / 0.6
Incidents · Bay of Bengal	2	41.2	0	—	1.3× / 1.6
Incidents · Solomon Sea	2	39.7	1	41	2.5× / 0.8
Missiles · Black Sea	2	39	0	—	0.3× / 6.6
Derelicts · Caribbean Sea	2	35.1	1	154	2.5× / 0.8
Surveys · Mediterranean Sea - Western Basin	2	28.9	1	35	10× / 0.2
Spills · Caribbean Seanew	2	28	1	22	new / 0
Surveys · Irish Sea and St. George's Channelnew	2	27.8	1	29	new / 0
Spills · The Coastal Waters of Southeast Alaska and British Columbia	2	24	1	45	2.5× / 0.8
Other · Coral Sea	2	20.1	1	19	10× / 0.2
Derelicts · Indian Ocean	2	14.4	0	—	0.6× / 3.6
Missiles · Arctic Ocean	2	13.7	0	—	2.5× / 0.8
Exercises · Celtic Seanew	2	10.8	0	—	new / 0
Cable ops · Mediterranean Sea - Eastern Basinnew	2	10.8	1	10	new / 0
Mines · North Pacific Oceannew	2	7.8	0	—	new / 0
Surveys · Bass Strait	2	7.4	0	—	2.0× / 1
Other · Caribbean Sea	2	7.3	0	—	10× / 0.2
Restricted · Gulf of Mexiconew	2	7.3	0	—	new / 0
Derelicts · Mediterranean Sea - Eastern Basin	2	6	0	—	3.3× / 0.6
Debris · North Atlantic Ocean	2	6	0	—	2.5× / 0.8
Debris · Philippine Seanew	2	6	0	—	new / 0
Storms · Philippine Seanew	2	5.3	0	—	new / 0
Surveys · Ligurian Sea	2	4.3	0	—	10× / 0.2
Quakes · Coral Sea	2	3	0	—	1.0× / 2
Incidents · Timor Sea	2	3	0	—	5.0× / 0.4
Other · The Coastal Waters of Southeast Alaska and British Columbianew	2	1.8	0	—	new / 0
Exercises · Coral Sea	2	1.2	2	1	1.3× / 1.6
Wrecks · The Northwestern Passages	2	0.7	2	0	2.5× / 0.8
Nav aids · Caribbean Sea	1	392.8	11	323	0.3× / 3.2
Wrecks · North Atlantic Oceanlong running	1	306.5	10	953	5.0× / 0.2
Nav aids · North Pacific Oceanlong running	1	186.9	6	760	0.2× / 5.4
Nav aids · Arabian Sea	1	154.8	5	91	0.6× / 1.8
Nav aids · Bay of Bengallong running	1	139.4	5	447	1.3× / 0.8
Wrecks · South Atlantic Ocean	1	115.4	4	225	1.3× / 0.8
Wrecks · North Pacific Oceanlong running	1	99.6	3	880	new / 0
Nav aids · Coral Sea	1	98.7	3	75	0.3× / 4
Nav aids · Mozambique Channel	1	88.5	3	321	new / 0
Surveys · Arctic Ocean	1	76.7	3	316	1.3× / 0.8
Ordnance · North Sealong running	1	68.6	3	687	0.6× / 1.6
Surveys · Indian Ocean	1	67.4	2	196	0.6× / 1.6
Nav aids · Bass Strait	1	56.8	2	70	2.5× / 0.4
Cable ops · Persian Gulf	1	54.6	1	282	2.5× / 0.4
Surveys · Barentsz Sea	1	52.2	2	133	0.8× / 1.2
Incidents · Java Sealong running	1	51.3	1	540	0.8× / 1.2
Nav aids · Davis Strait	1	42	0	—	0.4× / 2.4
Surveys · Davis Strait	1	39	1	36	new / 0
Other · North Pacific Ocean	1	34	1	151	0.1× / 7.4
Nav aids · Arafura Sea	1	33.4	1	91	2.5× / 0.4
Other · Gulf of Mexico	1	31	1	146	1.7× / 0.6
Exercises · Laccadive Sea	1	30.1	1	32	0.5× / 2.2
Nav aids · Irish Sea and St. George's Channel	1	29.7	0	—	0.6× / 1.6
Surveys · Celtic Sea	1	25.5	1	25	1.3× / 0.8
Cable ops · North Sea	1	24.1	0	—	0.3× / 3.2
Surveys · Baffin Bay	1	21.7	1	21	5.0× / 0.2
Exercises · Barentsz Sea	1	16.7	0	—	0.7× / 1.4
Mines · English Channel	1	16.6	0	—	new / 0
Derelicts · South China Sea	1	15.1	1	15	0.6× / 1.8
Spills · Gulf of Alaska	1	15	0	—	0.6× / 1.6
Surveys · Hudson Bay	1	13	1	13	new / 0
Incidents · Arabian Sea	1	12.8	1	31	0.5× / 2.2
Surveys · Hudson Strait	1	11.1	0	—	new / 0
Other · The Northwestern Passages	1	11	1	11	1.3× / 0.8
Exercises · Sea of Okhotsk	1	10.6	1	10	0.8× / 1.2
Missiles · Japan Sea	1	10	0	—	2.5× / 0.4
Nav aids · South China Sea	1	10	1	9	new / 0
Spills · Bering Sea	1	9	1	41	0.8× / 1.2
Restricted · Sea of Okhotsk	1	6.6	1	6	new / 0
Missiles · South Atlantic Ocean	1	6.4	0	—	2.5× / 0.4
Exercises · Caribbean Sea	1	5.7	0	—	0.4× / 2.4
Surveys · Great Australian Bight	1	5.6	1	5	new / 0
Quakes · Gulf of Alaska	1	5.2	0	—	2.5× / 0.4
Surveys · Bay of Bengal	1	5.1	1	5	0.4× / 2.8
Ordnance · North Pacific Ocean	1	4.1	1	4	new / 0
Wrecks · Kara Sea	1	3.7	1	3	new / 0
Wrecks · Java Sea	1	3.6	0	—	new / 0
Quakes · Aegean Sea	1	3	0	—	new / 0
Quakes · Arafura Sea	1	3	0	—	new / 0
Icebergs · Barentsz Sea	1	3	0	—	new / 0
Other · Barentsz Sea	1	3	0	—	new / 0
Quakes · Celebes Sea	1	3	0	—	2.5× / 0.4
Debris · Coral Sea	1	3	0	—	5.0× / 0.2
Debris · Gulf of Alaska	1	3	0	—	new / 0
Nav aids · Gulf of Alaska	1	3	0	—	0.6× / 1.6
Quakes · Gulf of Tomini	1	3	0	—	new / 0
Quakes · Indian Ocean	1	3	0	—	0.3× / 3.4
Derelicts · Tasman Sea	1	3	0	—	1.3× / 0.8
Missiles · Bay of Bengal	1	2.7	0	—	5.0× / 0.2
Nav aids · Adriatic Sea	1	1.9	0	—	new / 0
Missiles · Laccadive Sea	1	1.9	0	—	1.3× / 0.8
Cable ops · Bay of Biscay	1	1.6	1	1	new / 0
Derelicts · Coral Sea	1	1.6	0	—	5.0× / 0.2
Exercises · North Sea	1	1.5	0	—	new / 0
Cable ops · Caribbean Sea	1	1.4	1	1	0.6× / 1.6
Incidents · Davis Strait	1	1.4	0	—	5.0× / 0.2
Surveys · Ionian Sea	1	1.4	1	1	2.5× / 0.4
Cable ops · Mediterranean Sea - Western Basin	1	1.3	1	1	new / 0
Other · North Sea	1	1.3	1	1	0.7× / 1.4
Surveys · Arabian Sea	1	1	0	—	1.3× / 0.8
Spills · Mediterranean Sea - Eastern Basin	1	1	1	1	new / 0
Restricted · Mediterranean Sea - Eastern Basin	1	1	0	—	new / 0
Other · South China Sea	1	1	0	—	0.7× / 1.4
Exercises · Norwegian Sea	1	0.9	0	—	1.0× / 1
Incidents · Tasman Sea	1	0.9	0	—	1.0× / 1
Nav aids · Inner Seas off the West Coast of Scotland	1	0.8	0	—	0.3× / 3.2
Icebergs · Kara Sea	1	0.4	1	0	0.7× / 1.4
Nav aids · Bay of Biscay	1	0.1	0	—	new / 0
Storms · Caribbean Sea	1	0	0	—	2.5× / 0.4
Incidents · Great Australian Bight	1	0	0	—	new / 0
Nav aids · South Pacific Oceanlong running	0	257.6	7	1,030	0.0× / 5.2
Wrecks · South China Sealong running	0	248	8	926	0.0× / 1.2
Exercises · Aegean Sea	0	186	6	231	0.0× / 1.2
Wrecks · Arabian Sealong running	0	124	4	707	0.0× / 1
Wrecks · Persian Gulf	0	98.8	3	298	0.0× / 0.2
Exercises · Ionian Sea	0	93	3	231	— / 0
Other · Persian Gulflong running	0	93	3	421	— / 0
Nav aids · Mediterranean Sea - Eastern Basin	0	78.6	2	113	0.0× / 0.6
Wrecks · Bay of Bengal	0	62	2	68	0.0× / 0.2
Wrecks · English Channel	0	62	2	235	0.0× / 0.6
Surveys · Gulf of Guinea	0	62	2	87	0.0× / 0.2
Cable ops · Indian Ocean	0	62	2	74	0.0× / 1.6
Wrecks · Inner Seas off the West Coast of Scotland	0	62	2	326	0.0× / 0.2
Wrecks · Laccadive Sea	0	62	2	104	0.0× / 0.2
Restricted · South Atlantic Oceanlong running	0	62	2	607	0.0× / 1.4
Structures · South Atlantic Ocean	0	62	2	89	0.0× / 1
Nav aids · Tasman Sea	0	62	2	186	0.0× / 1.4
Nav aids · Andaman or Burma Sea	0	41.4	1	239	0.0× / 0.6
Wrecks · South Pacific Ocean	0	36	1	72	0.0× / 0.4
Missiles · Aegean Sea	0	31	1	231	— / 0

Cite: seahazards.com Sea Ledger, 2021-08, 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.