Sea Ledger, April 1999
1999-04-01 to 1999-04-30 · archive
- issued
- 288
- warning-days in force
- 3,635
- in force at month end
- 120
- sea × type cells
- 142
baseline: same month, previous 5 years — not available for this month (needs three fully collected reference months)
By type
| type | issued | warning-days | in force at end |
|---|---|---|---|
| Nav aids | 67 | 1,142.7 | 34 |
| Cable ops | 55 | 448.1 | 16 |
| Exercises | 42 | 302.1 | 5 |
| Incidents | 29 | 186.4 | 6 |
| Quakes | 25 | 101.7 | 4 |
| Surveys | 23 | 222.2 | 13 |
| Other | 16 | 410.7 | 15 |
| Missiles | 7 | 66.4 | 2 |
| Ordnance | 7 | 60.7 | 2 |
| Icebergs | 4 | 26.4 | 2 |
| Derelicts | 3 | 40.6 | 1 |
| Mines | 3 | 37.8 | 1 |
| Spills | 3 | 87 | 2 |
| Containers | 2 | 18.5 | 2 |
| War risk | 1 | 135.4 | 5 |
| Wrecks | 1 | 202 | 7 |
| Structures | 0 | 30 | 1 |
| Debris | 0 | 36 | 0 |
| Towing | 0 | 20 | 0 |
| Restricted | 0 | 30 | 1 |
| Volcanic | 0 | 30 | 1 |
By sea and type · 142 cells, most issued first
Cite: seahazards.com Sea Ledger, 1999-04, 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.