Sea Ledger, July 2021

2021-07-01 to 2021-07-31 · archive

issued: 666
warning-days in force: 10,881
in force at month end: 347
sea × type cells: 232

baseline: same month, previous 5 years (2020-07, 2019-07, 2018-07, 2017-07, 2016-07)

By type

type	issued	warning-days	in force at end
Exercises	120	1,356.8	40
Icebergs	101	122.8	6
Surveys	90	1,818.4	65
Incidents	74	598.9	19
Nav aids	61	3,115.6	101
Missiles	49	445.3	8
Quakes	43	119.4	8
Derelicts	36	209.2	5
Cable ops	22	454	15
Spills	17	270	6
Other	16	365.6	9
Wrecks	9	1,476.9	47
Storms	8	7.4	0
Piracy	7	36.4	1
Debris	5	15	0
Volcanic	2	161	6
Ordnance	2	69	2
Structures	1	82.1	2
Restricted	1	97.5	4
Mines	1	57.6	2
Containers	1	1.8	1

By sea and type · 200 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Exercises · North Pacific Ocean	35	349.2	12	79	1.6× / 21.4
Icebergs · South Atlantic Ocean	32	32	1	31	1.2× / 25.8
Icebergs · Southern Ocean	30	30	1	31	1.7× / 18
Icebergs · Labrador Sea	29	34.2	2	32	1.1× / 27.4
Surveys · South Atlantic Oceansurge	28	251	8	61	2.1× / 13.2
Surveys · North Atlantic Oceansurge	19	508.7	22	212	3.2× / 6
Exercises · Black Sea	18	260.5	5	49	0.8× / 24
Exercises · Bay of Bengalsurge	15	89.9	1	38	2.3× / 6.4
Incidents · South China Sealong running	14	204.1	5	481	0.5× / 27.6
Quakes · South Pacific Ocean	14	40.3	2	29	1.5× / 9.4
Missiles · North Atlantic Oceansurge	14	29.6	2	30	2.1× / 6.8
Incidents · North Pacific Ocean	13	99.9	4	48	0.6× / 23.6
Exercises · South Pacific Oceansurge	10	43.3	3	36	2.1× / 4.8
Nav aids · North Sea	9	180.5	5	179	1.2× / 7.6
Spills · North Pacific Oceansurge	9	128	1	42	3.2× / 2.8
Incidents · South Pacific Ocean	9	40.5	0	—	1.7× / 5.4
Incidents · Bay of Bengalsurge	8	95.7	3	37	5.7× / 1.4
Exercises · Philippine Sea	8	14.6	1	33	1.6× / 5
Surveys · North Sea	7	101.4	2	68	1.9× / 3.6
Exercises · Arabian Seasurge	7	52.2	2	33	2.7× / 2.6
Missiles · South Pacific Ocean	7	41	0	—	1.9× / 3.6
Incidents · South Atlantic Ocean	7	24.8	1	43	0.7× / 10.8
Storms · Gulf of Mexicosurge	7	7.1	0	—	3.9× / 1.8
Nav aids · South Atlantic Ocean	6	300.5	9	199	1.4× / 4.4
Missiles · Barentsz Seasurge	6	22.7	0	—	4.3× / 1.4
Quakes · Gulf of Alaskasurge	6	12.8	5	2	3.3× / 1.8
Nav aids · North Atlantic Oceanlong running	5	360.3	11	721	1.0× / 5.2
Nav aids · South Pacific Oceanlong running	5	294.8	10	999	1.1× / 4.4
Missiles · Black Sea	5	237.1	1	33	1.0× / 5
Surveys · Persian Gulfsurge	5	124.1	4	194	2.5× / 2
Cable ops · North Pacific Oceansurge	5	72.5	3	135	13× / 0.4
Missiles · North Pacific Ocean	5	49.1	3	46	1.1× / 4.4
Exercises · Andaman or Burma Seasurge	5	19.1	0	—	4.2× / 1.2
Derelicts · North Atlantic Ocean	5	15.7	0	—	1.7× / 3
Derelicts · Tasman Seasurge	5	5.8	0	—	25× / 0.2
Nav aids · Caribbean Sea	4	322.7	12	292	1.5× / 2.6
Nav aids · North Pacific Oceanlong running	4	211	6	729	0.9× / 4.6
Cable ops · North Atlantic Ocean	4	127.4	5	48	0.5× / 7.8
Exercises · South Atlantic Ocean	4	42.8	2	36	0.5× / 8.2
Surveys · Kara Sea	4	37.7	4	17	1.2× / 3.4
Incidents · Philippine Sea	4	34.2	1	36	1.0× / 4
Nav aids · Celtic Seasurge	4	33.7	1	57	4.0× / 1
Surveys · Davis Straitnew	4	25.2	2	12	new / 0
Nav aids · The Northwestern Passagessurge	4	19.6	1	27	20× / 0.2
Incidents · Solomon Seasurge	4	14.1	1	23	3.3× / 1.2
Quakes · North Pacific Ocean	4	12	0	—	0.7× / 5.4
Derelicts · Celtic Seanew	4	8.6	0	—	new / 0
Missiles · Gulf of Mexicosurge	4	7	0	—	20× / 0.2
Missiles · Indian Ocean	4	6.8	1	6	1.3× / 3.2
Derelicts · Indian Ocean	4	5.3	2	11	1.4× / 2.8
Incidents · Tasman Seasurge	4	0.6	0	—	5.0× / 0.8
Nav aids · Coral Sea	3	124.7	3	57	1.0× / 3
Surveys · Indian Oceansurge	3	92.5	2	165	3.8× / 0.8
Surveys · Norwegian Sea	3	74.6	4	55	0.8× / 4
Spills · Gulf of Mexico	3	69	1	45	0.4× / 6.8
Derelicts · Caribbean Seasurge	3	46	1	123	3.0× / 1
Spills · The Coastal Waters of Southeast Alaska and British Columbiasurge	3	38	2	19	3.0× / 1
Surveys · North Pacific Oceansurge	3	33.9	0	—	3.0× / 1
Cable ops · Eastern China Seasurge	3	22.6	0	—	3.8× / 0.8
Missiles · Japan Seasurge	3	12.8	0	—	2.1× / 1.4
Quakes · Bismarck Seasurge	3	9	0	—	15× / 0.2
Quakes · Indian Ocean	3	9	0	—	1.3× / 2.4
Icebergs · Laptev Sea	3	9	0	—	1.9× / 1.6
Derelicts · Mediterranean Sea - Western Basinsurge	3	9	0	—	3.8× / 0.8
Quakes · Molukka Seasurge	3	9	0	—	2.5× / 1.2
Nav aids · Gulf of Alaska	3	8.6	1	29	1.5× / 2
Exercises · Mediterranean Sea - Western Basinsurge	3	4.8	1	24	15× / 0.2
Incidents · Coral Sea	3	0.3	0	—	0.6× / 5.2
Wrecks · Persian Gulflong running	2	200.1	4	593	5.0× / 0.4
Nav aids · Arabian Sea	2	169.2	5	208	2.5× / 0.8
Volcanic · Philippine Sea	2	99	4	225	5.0× / 0.4
Surveys · South Pacific Oceanlong running	2	58.2	2	668	10× / 0.2
Derelicts · Arabian Sealong running	2	48	1	554	10× / 0.2
Incidents · Java Sealong running	2	41.6	1	509	1.4× / 1.4
Exercises · Mediterranean Sea - Eastern Basin	2	33.1	1	43	0.1× / 15.2
Nav aids · English Channel	2	31.6	1	52	1.1× / 1.8
Exercises · Laccadive Sea	2	30.3	1	30	1.1× / 1.8
Surveys · Mediterranean Sea - Western Basin	2	30.1	1	52	10× / 0.2
Other · North Atlantic Ocean	2	20.8	0	—	1.7× / 1.2
Wrecks · Bristol Channel	2	20.4	1	25	10× / 0.2
Other · Coral Sea	2	16.2	0	—	2.0× / 1
Cable ops · North Sea	2	14.9	0	—	1.0× / 2
Surveys · Gulf of Mexico	2	14.7	1	31	5.0× / 0.4
Piracy · Singapore Straitnew	2	14	0	—	new / 0
Exercises · Indian Ocean	2	13.5	0	—	3.3× / 0.6
Icebergs · Kara Sea	2	8.5	0	—	2.0× / 1
Cable ops · Celtic Sea	2	6.4	1	6	1.4× / 1.4
Derelicts · Alboran Seanew	2	6	0	—	new / 0
Quakes · Gulf of Tomini	2	6	0	—	5.0× / 0.4
Debris · Indian Ocean	2	6	0	—	1.1× / 1.8
Quakes · Philippine Sea	2	6	0	—	0.8× / 2.6
Derelicts · Bay of Biscay	2	5.1	0	—	5.0× / 0.4
Icebergs · East Siberian Seanew	2	3.8	2	2	new / 0
Derelicts · South China Sea	2	3.1	0	—	1.1× / 1.8
Other · Caribbean Sea	2	3	0	—	3.3× / 0.6
Incidents · Arabian Seanew	2	2.3	1	2	new / 0
Icebergs · Davis Strait	2	2.3	0	—	1.7× / 1.2
Incidents · Indian Ocean	2	1.8	1	22	0.4× / 5
Piracy · Arabian Seanew	2	1.4	1	1	new / 0
Exercises · North Seanew	2	0.4	0	—	new / 0
Nav aids · Hudson Baynew	2	0	0	—	new / 0
Nav aids · Bay of Bengallong running	1	117.4	4	416	5.0× / 0.2
Nav aids · Mediterranean Sea - Western Basinlong running	1	111.6	4	426	1.0× / 1
Wrecks · Arabian Sealong running	1	101.4	4	676	1.3× / 0.8
Nav aids · Indian Ocean	1	86.4	2	112	1.0× / 1
Nav aids · Mediterranean Sea - Eastern Basin	1	86.1	3	82	5.0× / 0.2
Surveys · Sea of Okhotsk	1	72	3	43	0.4× / 2.4
Structures · South Atlantic Ocean	1	66.5	2	58	5.0× / 0.2
Cable ops · Persian Gulf	1	60.3	2	251	5.0× / 0.2
Wrecks · South Pacific Ocean	1	59.7	2	41	1.7× / 0.6
Surveys · Gulf of Guinea	1	57.4	2	56	new / 0
Cable ops · Indian Ocean	1	56.6	2	45	1.3× / 0.8
Wrecks · Bay of Bengal	1	44.3	2	37	5.0× / 0.2
Surveys · Mediterranean Sea - Eastern Basin	1	42.5	0	—	0.4× / 2.6
Wrecks · Caribbean Sea	1	41.2	1	130	2.5× / 0.4
Nav aids · Great Australian Bight	1	31.9	1	45	1.0× / 1
Surveys · Bay of Biscay	1	29.5	1	38	new / 0
Mines · English Channel	1	26.6	1	26	new / 0
Surveys · Mozambique Channel	1	21.1	0	—	5.0× / 0.2
Exercises · Gulf of Mexico	1	20.2	0	—	0.6× / 1.6
Spills · Bering Sea	1	17	1	38	0.6× / 1.6
Incidents · Andaman or Burma Sea	1	16.9	1	31	new / 0
Derelicts · South Pacific Ocean	1	16.6	0	—	0.4× / 2.4
Exercises · North Atlantic Ocean	1	16	0	—	0.2× / 4.8
Exercises · Norwegian Sea	1	16	0	—	new / 0
Surveys · Bering Sea	1	15.2	1	15	1.0× / 1
Other · Kara Sea	1	14.6	1	14	5.0× / 0.2
Exercises · Barentsz Sea	1	14.4	1	38	0.8× / 1.2
Spills · Gulf of Alaska	1	13	1	13	0.8× / 1.2
Nav aids · Irish Sea and St. George's Channel	1	13	1	12	0.6× / 1.6
Surveys · Tyrrhenian Sea	1	12.4	1	12	new / 0
Nav aids · Davis Strait	1	12.1	1	12	2.5× / 0.4
Cable ops · South China Sea	1	10.8	0	—	0.6× / 1.6
Exercises · Japan Sea	1	10.3	0	—	1.0× / 1
Cable ops · Strait of Gibraltar	1	10.3	1	10	new / 0
Nav aids · Laccadive Sea	1	9.4	1	9	new / 0
Exercises · Caribbean Sea	1	8.2	0	—	0.6× / 1.8
Exercises · Bering Sea	1	7.7	0	—	0.8× / 1.2
Piracy · Caribbean Sea	1	7	0	—	new / 0
Piracy · North Atlantic Ocean	1	7	0	—	2.5× / 0.4
Piracy · South Atlantic Ocean	1	7	0	—	5.0× / 0.2
Restricted · Kara Sea	1	4.5	1	4	new / 0
Ordnance · North Pacific Ocean	1	4	0	—	new / 0
Cable ops · English Channel	1	3.8	0	—	5.0× / 0.2
Other · Timor Sea	1	3.1	0	—	new / 0
Debris · Arabian Sea	1	3	0	—	new / 0
Quakes · Arabian Sea	1	3	0	—	1.7× / 0.6
Icebergs · Arctic Ocean	1	3	0	—	new / 0
Ordnance · Barentsz Sea	1	3	0	—	new / 0
Derelicts · Bay of Bengal	1	3	0	—	2.5× / 0.4
Debris · Celtic Sea	1	3	0	—	new / 0
Quakes · Coral Sea	1	3	0	—	0.4× / 2.6
Derelicts · English Channel	1	3	0	—	5.0× / 0.2
Quakes · Greenland Sea	1	3	0	—	new / 0
Other · Indian Ocean	1	3	0	—	5.0× / 0.2
Quakes · North Atlantic Ocean	1	3	0	—	1.7× / 0.6
Derelicts · North Sea	1	3	0	—	new / 0
Quakes · South Atlantic Ocean	1	3	0	—	1.0× / 1
Debris · South Pacific Ocean	1	3	0	—	1.3× / 0.8
Cable ops · Mediterranean Sea - Western Basin	1	2.8	0	—	new / 0
Other · Tasman Sea	1	2.8	0	—	1.3× / 0.8
Wrecks · Gulf of Oman	1	2.2	1	2	new / 0
Other · The Coastal Waters of Southeast Alaska and British Columbia	1	2.1	0	—	5.0× / 0.2
Other · Gulf of Alaska	1	2	0	—	2.5× / 0.4
Other · Hudson Strait	1	2	0	—	5.0× / 0.2
Surveys · Irish Sea and St. George's Channel	1	1.9	0	—	new / 0
Missiles · Laccadive Sea	1	1.9	0	—	1.3× / 0.8
Containers · South Atlantic Ocean	1	1.8	1	1	5.0× / 0.2
Other · South China Sea	1	1.6	0	—	1.7× / 0.6
Other · North Sea	1	0.4	0	—	0.4× / 2.4
Storms · Caribbean Sea	1	0.3	0	—	5.0× / 0.2
Quakes · Gulf of California	1	0.3	1	0	new / 0
Incidents · Arafura Sea	1	0.2	0	—	0.5× / 2.2
Other · Hudson Bay	1	0.2	0	—	1.3× / 0.8
Wrecks · North Atlantic Oceanlong running	0	279	9	922	— / 0
Wrecks · South China Sealong running	0	263.6	8	895	0.0× / 1.6
Exercises · Aegean Sea	0	186	6	200	0.0× / 2.4
Nav aids · Gulf of Mexico	0	186	6	238	0.0× / 3.4
Exercises · Ionian Sea	0	93	3	200	— / 0
Wrecks · North Pacific Oceanlong running	0	93	3	849	0.0× / 0.2
Other · Persian Gulflong running	0	93	3	390	0.0× / 0.2
Wrecks · South Atlantic Ocean	0	93	3	194	0.0× / 1.4
Surveys · Barentsz Sea	0	79.3	1	197	0.0× / 2
Nav aids · Andaman or Burma Sea	0	62	2	208	0.0× / 1
Surveys · Arctic Ocean	0	62	2	285	0.0× / 0.4
Wrecks · English Channel	0	62	2	204	0.0× / 0.2
Wrecks · Inner Seas off the West Coast of Scotland	0	62	2	295	— / 0
Wrecks · Laccadive Sea	0	62	2	73	— / 0
Nav aids · Mozambique Channel	0	62	2	290	0.0× / 0.2
Ordnance · North Sealong running	0	62	2	656	0.0× / 2.2
Restricted · South Atlantic Oceanlong running	0	62	2	576	0.0× / 1
Nav aids · Tasman Sea	0	62	2	155	0.0× / 0.4
Surveys · Black Sea	0	42	1	143	0.0× / 1.4
Missiles · Aegean Sea	0	31	1	200	0.0× / 0.2
Nav aids · Arafura Sea	0	31	1	60	0.0× / 0.4
Other · Arafura Sea	0	31	1	115	0.0× / 0.2
Nav aids · Bass Strait	0	31	1	39	— / 0
Cable ops · Black Sea	0	31	1	186	0.0× / 0.4
Nav aids · Black Sea	0	31	1	107	0.0× / 0.2
Volcanic · Caribbean Sea	0	31	1	110	— / 0

Cite: seahazards.com Sea Ledger, 2021-07, 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.