Storm history › South Indian Ocean › 1977 season
Cyclone Io / Jack (1977)
Io / Jack was a Category 1 cyclone of the 1977 South Indian Ocean season. It was tracked from February 13, 1977 to March 2, 1977, about 18 days, and covered 4,335 miles.
At its peak it had winds of 80 mph (130 km/h) and a lowest pressure of 975 mb.
- Peak wind
- 80 mph
- Lowest pressure
- 975 mb
- Strongest
- Category 1 cyclone
- Duration
- 18 days
- Track length
- 4,335 mi
- Energy (ACE)
- 6.1
DepressionTropical stormCat 1Cat 2Cat 3Cat 4Cat 5
How it compares
- Peak winds: 363rd highest of 951 South Indian Ocean storms on record, tied with Cyclone Honde (2025), Cyclone Chalane (2021), Cyclone Flamboyan (2018) and 23 more.
- Lowest pressure: 457th lowest of 1,029 South Indian Ocean storms with a recorded pressure, tied with Cyclone Jude (2025), Tropical Storm Fezile (2022), Tropical Storm Terri (2001) and 12 more.
- Energy: 16% of the 1977 South Indian Ocean season's ACE.