Sea Ledger, April 1997
1997-04-01 to 1997-04-30 · archive
- issued
- 54
- warning-days in force
- 807
- in force at month end
- 25
- sea × type cells
- 39
baseline: same month, previous 5 years — not available for this month (needs three fully collected reference months)
By type
By sea and type · 39 cells, most issued first
Cite: seahazards.com Sea Ledger, 1997-04, 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.