Sea Ledger, May 2023

2023-05-01 to 2023-05-31 · archive

issued: 746
warning-days in force: 14,420
in force at month end: 457
sea × type cells: 231

baseline: same month, previous 5 years (2022-05, 2021-05, 2020-05, 2019-05, 2018-05)

By type

type	issued	warning-days	in force at end
Exercises	168	1,423	37
Incidents	117	1,029.8	34
Icebergs	97	104.6	5
Surveys	67	2,969.1	93
Nav aids	62	4,712	148
Missiles	59	359.1	19
Quakes	43	116.6	5
Derelicts	29	243.8	6
Cable ops	24	589.4	22
Towing	21	23.4	0
Other	16	716.7	19
Wrecks	16	1,302.4	45
Spills	8	137.7	4
Debris	7	118.5	3
Storms	4	8.8	0
Mines	2	65.9	2
Piracy	2	10	0
Ordnance	2	40.3	1
Restricted	1	64.6	2
Volcanic	1	224.5	7
Structures	0	97.6	3
War risk	0	31	1
Containers	0	31	1

By sea and type · 200 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Icebergs · Southern Ocean	33	34.8	2	31	0.8× / 39.2
Icebergs · Labrador Sea	31	36.7	2	32	1.3× / 23.4
Icebergs · South Atlantic Ocean	31	29.9	1	31	1.3× / 24.6
Exercises · North Pacific Ocean	28	348.2	9	65	1.0× / 26.8
Incidents · South China Sea	22	171.3	6	83	1.0× / 22.6
Quakes · South Pacific Ocean	21	59	1	33	1.8× / 11.6
Towing · North Pacific Oceansurge	21	23.4	0	—	7.5× / 2.8
Incidents · North Atlantic Ocean	19	205.8	9	208	1.8× / 10.6
Exercises · Arabian Sea	15	86.9	2	33	2.0× / 7.6
Incidents · Indian Ocean	15	62.4	3	42	1.8× / 8.2
Incidents · Mediterranean Sea - Eastern Basinsurge	14	157.4	2	46	2.5× / 5.6
Nav aids · South Atlantic Ocean	13	1,479.2	46	292	1.2× / 10.6
Exercises · Laccadive Seasurge	13	69.8	2	33	7.2× / 1.8
Missiles · North Atlantic Ocean	13	44.3	2	32	1.2× / 11.2
Surveys · Arabian Sea	12	349.1	8	133	1.5× / 8.2
Exercises · South Atlantic Ocean	12	99.1	3	40	1.9× / 6.2
Exercises · South Pacific Ocean	12	61.1	0	—	0.9× / 12.8
Exercises · North Atlantic Ocean	11	90.1	4	165	1.3× / 8.8
Missiles · South Pacific Oceansurge	11	66.4	3	41	2.8× / 4
Exercises · Bay of Bengal	11	51.4	1	34	1.2× / 9.4
Exercises · Gulf of Mexicosurge	10	90	1	14	7.1× / 1.4
Exercises · Celtic Seasurge	10	21.5	1	33	50× / 0.2
Nav aids · North Seasurge	9	197.5	7	356	2.0× / 4.4
Surveys · South Atlantic Ocean	9	132.8	2	248	0.6× / 14.4
Incidents · North Pacific Ocean	9	78.6	2	33	0.7× / 12.6
Missiles · Indian Ocean	9	69.2	0	—	2.0× / 4.6
Surveys · Bay of Bengalsurge	8	117.3	4	131	5.0× / 1.6
Exercises · Bay of Biscaysurge	8	24.6	2	29	40× / 0.2
Exercises · Barentsz Seasurge	7	46.7	1	35	3.9× / 1.8
Derelicts · North Atlantic Oceansurge	7	46.1	0	—	2.2× / 3.2
Exercises · Andaman or Burma Seasurge	7	27.8	1	33	2.7× / 2.6
Nav aids · North Atlantic Oceanlong running	6	335	11	776	0.8× / 7.2
Cable ops · Arabian Seasurge	6	146.7	3	105	7.5× / 0.8
Wrecks · South Atlantic Oceansurgelong running	6	115.7	6	369	4.3× / 1.4
Cable ops · North Atlantic Ocean	6	97.6	5	38	0.9× / 6.6
Exercises · Black Sealong running	6	72.5	2	434	0.5× / 11.4
Derelicts · Gulf of Mexicosurge	6	27	2	33	7.5× / 0.8
Quakes · North Pacific Ocean	6	14.4	2	26	0.9× / 6.8
Incidents · Bay of Bengalsurge	6	8.9	0	—	7.5× / 0.8
Surveys · North Atlantic Ocean	5	778.3	26	344	0.6× / 7.8
Other · North Atlantic Oceansurge	5	134.8	3	254	2.8× / 1.8
Incidents · South Pacific Ocean	5	68.6	2	43	0.8× / 6.6
Surveys · Caribbean Seasurge	5	67	3	213	6.3× / 0.8
Incidents · Gulf of Mexico	5	62.5	1	150	1.9× / 2.6
Missiles · Barentsz Sea	5	35.4	2	19	1.2× / 4.2
Nav aids · English Channel	5	12.5	0	—	1.7× / 3
Nav aids · Inner Seas off the West Coast of Scotland	5	12.2	0	—	1.6× / 3.2
Nav aids · South Pacific Oceanlong running	4	550.7	17	433	1.1× / 3.8
Surveys · Persian Gulflong running	4	295.2	10	863	0.9× / 4.6
Surveys · Indian Ocean	4	171.9	4	96	1.8× / 2.2
Wrecks · Arabian Seasurgelong running	4	146.7	7	365	4.0× / 1
Spills · Gulf of Mexico	4	63	1	41	0.9× / 4.4
Incidents · Arabian Sea	4	60.3	2	26	0.9× / 4.2
Missiles · Japan Sea	4	13.8	3	12	1.4× / 2.8
Debris · North Pacific Oceansurge	4	13.7	0	—	10× / 0.4
Quakes · Philippine Sea	4	12	0	—	1.3× / 3
Storms · Philippine Seanew	4	8.8	0	—	new / 0
Derelicts · Indian Ocean	4	8.3	0	—	1.3× / 3.2
Nav aids · North Pacific Oceanlong running	3	161.2	5	420	1.5× / 2
Nav aids · Indian Oceansurge	3	59.3	1	48	3.8× / 0.8
Exercises · Japan Sea	3	40.6	0	—	1.9× / 1.6
Derelicts · Laccadive Seasurge	3	38.8	1	343	7.5× / 0.4
Other · Coral Seasurgelong running	3	38.2	1	406	15× / 0.2
Exercises · Caribbean Seasurge	3	29.3	0	—	3.0× / 1
Exercises · Gulf of Californianew	3	24.8	0	—	new / 0
Surveys · Sea of Okhotsksurge	3	21.4	2	13	2.1× / 1.4
Incidents · Mozambique Channelsurge	3	13.9	3	9	7.5× / 0.4
Missiles · Philippine Seanew	3	10.2	1	12	new / 0
Derelicts · Caribbean Seasurge	3	9	0	—	2.1× / 1.4
Exercises · Coral Sea	3	7.5	0	—	1.9× / 1.6
Incidents · Coral Sea	3	3.1	0	—	1.1× / 2.6
Cable ops · Bay of Bengalsurge	3	2.9	2	2	15× / 0.2
Nav aids · Gulf of Mexicolong running	2	236.4	8	789	1.4× / 1.4
Surveys · Norwegian Sea	2	123.7	5	46	1.1× / 1.8
Surveys · Barentsz Sea	2	88.2	3	324	2.5× / 0.8
Nav aids · Coral Sea	2	76.5	1	79	0.4× / 5.6
Nav aids · Irish Sea and St. George's Channel	2	60.2	2	335	0.8× / 2.4
Spills · North Atlantic Ocean	2	48.7	1	314	0.6× / 3.4
Surveys · Andaman or Burma Sea	2	38	1	44	2.0× / 1
Missiles · North Pacific Ocean	2	37.4	2	92	0.4× / 5.2
Derelicts · South Atlantic Ocean	2	37	1	74	0.5× / 3.8
Incidents · Philippine Sea	2	21.6	2	14	0.6× / 3.4
Cable ops · North Pacific Ocean	2	21.4	2	13	0.8× / 2.4
Other · Gulf of Mexico	2	17.8	0	—	3.3× / 0.6
Exercises · Philippine Sea	2	15.9	0	—	1.0× / 2
Surveys · Gulf of Guinea	2	9.5	1	9	5.0× / 0.4
Ordnance · North Pacific Ocean	2	9.3	0	—	10× / 0.2
Exercises · Bering Seanew	2	8.9	1	13	new / 0
Missiles · South Atlantic Ocean	2	8.3	2	4	10× / 0.2
Quakes · Japan Seanew	2	6	0	—	new / 0
Missiles · Norwegian Sea	2	5.4	1	25	5.0× / 0.4
Quakes · South Atlantic Ocean	2	5.1	1	33	1.7× / 1.2
Incidents · Solomon Sea	2	2.5	0	—	5.0× / 0.4
Missiles · South China Sea	2	2.3	0	—	1.7× / 1.2
Nav aids · Caribbean Sealong running	1	773.4	25	834	0.3× / 3
Volcanic · Philippine Sealong running	1	193.5	6	894	new / 0
Cable ops · Persian Gulflong running	1	180.6	5	657	1.7× / 0.6
Wrecks · Persian Gulflong running	1	164.3	4	488	5.0× / 0.2
Wrecks · Caribbean Sea	1	140.3	5	252	2.5× / 0.4
Nav aids · Laccadive Sea	1	125.5	4	351	1.7× / 0.6
Surveys · Black Sea	1	113.5	3	118	2.5× / 0.4
Wrecks · Laccadive Sea	1	95.6	3	103	2.5× / 0.4
Other · South Atlantic Ocean	1	93	3	134	1.7× / 0.6
Surveys · Laccadive Sealong running	1	89.8	1	473	2.5× / 0.4
Nav aids · Persian Gulflong running	1	70.4	3	372	5.0× / 0.2
Surveys · Bass Strait	1	68.3	2	55	5.0× / 0.2
Mines · Black Sealong running	1	65	2	461	new / 0
Nav aids · Arabian Sealong running	1	64.1	2	581	0.8× / 1.2
Other · Caribbean Sealong running	1	62.8	3	580	new / 0
Surveys · Gulf of Mexico	1	62	2	181	1.0× / 1
Wrecks · South Pacific Ocean	1	58.1	2	58	1.3× / 0.8
Nav aids · Andaman or Burma Sea	1	54.4	2	254	2.5× / 0.4
Surveys · South Pacific Ocean	1	37.6	2	71	1.7× / 0.6
Derelicts · Bay of Bengal	1	36	1	348	0.8× / 1.2
Derelicts · South Pacific Ocean	1	35.2	1	240	0.4× / 2.4
Debris · South Pacific Ocean	1	34	1	125	0.7× / 1.4
Nav aids · Beaufort Sea	1	31.6	1	293	5.0× / 0.2
Wrecks · Arafura Sea	1	30.5	1	30	new / 0
Spills · North Pacific Ocean	1	20	1	37	0.3× / 3.8
Incidents · South Atlantic Ocean	1	17.7	1	17	0.2× / 4.2
Other · Tasman Sea	1	17.3	0	—	5.0× / 0.2
Surveys · Coral Sea	1	16.9	1	16	new / 0
Incidents · Adriatic Sea	1	16.8	0	—	new / 0
Surveys · Philippine Sea	1	14.8	0	—	5.0× / 0.2
Missiles · Arctic Ocean	1	13.3	0	—	5.0× / 0.2
Incidents · Laccadive Sea	1	11.3	0	—	0.4× / 2.4
Missiles · Black Sea	1	9.4	0	—	0.3× / 3
Surveys · North Pacific Ocean	1	8.5	1	8	1.3× / 0.8
Missiles · Tasman Sea	1	8	1	8	new / 0
Cable ops · Singapore Strait	1	7.7	0	—	new / 0
Piracy · Gulf of Guinea	1	7	0	—	0.3× / 3
Nav aids · Bristol Channel	1	6.9	0	—	2.5× / 0.4
Surveys · Bay of Biscay	1	6.4	1	6	new / 0
Spills · Bering Sea	1	6	1	6	new / 0
Cable ops · Eastern China Sea	1	6	0	—	1.7× / 0.6
Cable ops · South China Sea	1	5	0	—	0.7× / 1.4
Cable ops · Yellow Sea	1	4.7	1	4	new / 0
Incidents · English Channel	1	4.5	1	4	new / 0
Cable ops · Labrador Sea	1	4	0	—	new / 0
Incidents · Gulf of Thailand	1	3.9	0	—	1.7× / 0.6
Derelicts · North Pacific Ocean	1	3.4	0	—	0.3× / 3.8
Quakes · Banda Sea	1	3	0	—	1.7× / 0.6
Derelicts · Barentsz Sea	1	3	0	—	new / 0
Debris · Caribbean Sea	1	3	0	—	new / 0
Quakes · Caribbean Sea	1	3	0	—	new / 0
Quakes · Eastern China Sea	1	3	0	—	1.7× / 0.6
Quakes · Gulf of Aden	1	3	0	—	new / 0
Quakes · Indian Ocean	1	3	0	—	0.4× / 2.6
Other · Indian Ocean	1	3	0	—	1.7× / 0.6
Debris · North Atlantic Ocean	1	3	0	—	0.7× / 1.4
Quakes · Solomon Sea	1	3	0	—	1.0× / 1
Piracy · South China Sea	1	3	0	—	new / 0
Icebergs · South Pacific Ocean	1	3	0	—	new / 0
Restricted · Philippine Sea	1	2.6	0	—	new / 0
Incidents · Celebes Sea	1	2.4	0	—	5.0× / 0.2
Missiles · Bay of Bengal	1	2.3	0	—	2.5× / 0.4
Nav aids · Bay of Bengal	1	2	0	—	1.7× / 0.6
Missiles · Laccadive Sea	1	1.8	0	—	1.7× / 0.6
Exercises · Red Sea	1	1.5	0	—	1.3× / 0.8
Other · Celtic Sea	1	1.2	0	—	new / 0
Wrecks · East Siberian Sea	1	1.1	0	—	new / 0
Mines · Persian Gulf	1	0.9	0	—	5.0× / 0.2
Quakes · Tasman Sea	1	0.9	1	0	5.0× / 0.2
Missiles · Sea of Okhotsk	1	0.6	1	0	2.5× / 0.4
Incidents · Tasman Sea	1	0.4	0	—	1.3× / 0.8
Cable ops · Celtic Sea	1	0.3	1	0	1.7× / 0.6
Other · South China Sea	1	0.3	0	—	5.0× / 0.2
Icebergs · Gulf of St. Lawrence	1	0.2	0	—	new / 0
Exercises · Baltic Sea	1	0.1	1	0	2.5× / 0.4
Quakes · Coral Sea	1	0.1	0	—	0.5× / 2
Incidents · Molukka Sea	1	0	0	—	5.0× / 0.2
Exercises · Aegean Sea	0	155	5	149	0.0× / 7.8
Surveys · The Northwestern Passages	0	155	5	285	— / 0
Wrecks · The Northwestern Passageslong running	0	155	5	636	— / 0
Other · Persian Gulf	0	128.4	3	300	0.0× / 0.4
Surveys · Kara Sea	0	124	4	324	— / 0
Nav aids · Bay of Biscay	0	93	3	306	— / 0
Wrecks · South China Sealong running	0	93	3	1,546	0.0× / 0.2
Nav aids · Celtic Sea	0	62	2	285	0.0× / 1.2
Wrecks · Hudson Bay	0	62	2	215	— / 0
Wrecks · North Sealong running	0	62	2	536	0.0× / 0.2
Structures · South Atlantic Ocean	0	62	2	306	0.0× / 0.2
Other · Arabian Sealong running	0	49.6	1	629	0.0× / 0.8
Wrecks · North Atlantic Oceanlong running	0	49.6	1	735	0.0× / 1
Incidents · Caribbean Sea	0	37.3	0	—	0.0× / 3.8
Debris · Bay of Biscay	0	33.8	1	266	— / 0
Missiles · Aegean Sea	0	31	1	149	0.0× / 0.6
Cable ops · Andaman or Burma Sea	0	31	1	44	— / 0
Nav aids · Arctic Ocean	0	31	1	252	— / 0
Surveys · Arctic Ocean	0	31	1	262	— / 0
Nav aids · Barentsz Sea	0	31	1	200	— / 0
Other · Bay of Biscay	0	31	1	133	— / 0
Nav aids · Bering Sea	0	31	1	159	— / 0
Other · Black Sea	0	31	1	73	0.0× / 0.4
War risk · Black Sealong running	0	31	1	435	— / 0
Wrecks · Coral Sea	0	31	1	334	— / 0
Other · English Channel	0	31	1	128	0.0× / 1.2
Nav aids · Gulf of Californialong running	0	31	1	411	— / 0
Wrecks · Gulf of Mexicolong running	0	31	1	444	— / 0
Nav aids · Hudson Bay	0	31	1	259	— / 0

Cite: seahazards.com Sea Ledger, 2023-05, 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.