Cyclone Alison (1975)

Basin

South Pacific

Dates

March 3, 1975 to March 13, 1975

Peak strength

Cyclone, 85 kt (98 mph), ten-minute wind

Lowest pressure

945 mb (27.91 inHg)

Landfall

Yes

Accumulated cyclone energy

7.2

Identifier

SH231975

No source this site reads publishes a machine-readable casualty or damage figure for a storm of this era. The National Hurricane Center’s season tables begin in 1995 and carry deaths and damage only from 2005 in the Atlantic and 2020 in both basins; the US Storm Events record begins in 1996.

• Unnamed tropical depressionSouth Pacific · 1975Tropical Depression
• Unnamed tropical depressionSouth Pacific · 1975Tropical Depression
• Unnamed tropical depressionSouth Pacific · 1975Tropical Depression
• Unnamed tropical depressionSouth Pacific · 1975Tropical Depression
• Unnamed tropical depressionSouth Pacific · 1975Tropical Depression
• Cyclone TracySouth Pacific · 1975Cat 295 kt · 950 mb
• Tropical Storm FloraSouth Pacific · 1975Tropical Storm55 kt · 980 mb
• Unnamed tropical depressionSouth Pacific · 1975Tropical Depression
• Tropical Storm GloriaSouth Pacific · 1975Tropical Storm55 kt · 980 mb
• Tropical Storm FloraSouth Pacific · 1975Tropical Storm40 kt · 990 mb
• Unnamed tropical depressionSouth Pacific · 1975Tropical Depression
• Cyclone ValSouth Pacific · 1975Cyclone85 kt · 945 mb
• Unnamed tropical depressionSouth Pacific · 1975Tropical Depression
• Cyclone BettySouth Pacific · 1975Cyclone70 kt · 965 mb
• Tropical Storm AmeliaSouth Pacific · 1975Tropical Storm35 kt · 990 mb

A best track is the record a warning agency settles on after the storm, not what it said at the time: position, maximum sustained wind and central pressure every six hours, revised against every observation that came in later. Category is the Saffir-Simpson scale, which runs from Category 1 at 64 kt to Category 5 at 137 kt and reads wind only, so it says nothing about surge or rain. Accumulated cyclone energy adds up the square of the wind through the storm's life, so it counts strength and duration together. This storm’s winds are ten-minute averages from its regional agency. They read about 12 percent lower than the one-minute winds US agencies use, so a Saffir-Simpson category is not given for it.

Storm history from NOAA NCEI’s International Best Track Archive for Climate Stewardship (IBTrACS), which merges the official best track of every warning agency. Live storms, cones, watches and warnings from the National Hurricane Center and the Central Pacific Hurricane Center. Archived radar from NOAA’s Level II archive.