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How Strong Was Tropical Cyclone Alfred?

Alfred peaked as an Australian category 4 severe tropical cyclone far offshore, with 10-minute sustained winds of 165 km/h. It later weakened, briefly re-intensified, reached Moreton Island at category 1 strength and fell below tropical-cyclone strength before the remnant crossed mainland southeast Queensland.

Timeline

  1. 2025-02-21: Tropical Low 22U formed northeast of Cooktown.
  2. 2025-02-23: The Bureau named the system Tropical Cyclone Alfred.
  3. 2025-02-27 to 2025-02-28: Alfred held its lifetime peak at category 4, with 10-minute mean winds of 165 km/h, well offshore.
  4. 2025-03-06: After weakening and a period of subtropical structure, Alfred re-intensified to category 2 while moving west.
  5. 2025-03-08: Alfred crossed Moreton Island at category 1, weakened below tropical-cyclone strength, and later moved onto the mainland as a subtropical system.

Severe Tropical Cyclone Alfred reached category 4 on the Australian scale while it was well offshore in the Coral Sea. The Bureau of Meteorology’s post-event analysis gives a peak 10-minute mean wind of 90 knots, or 165 km/h, from early to late on February 28 local time. That was Alfred’s maximum intensity, but it was not its intensity when it approached Brisbane or when the remnant circulation reached the mainland. [1][2]

Australia ranks tropical cyclones from category 1 to 5 using maximum 10-minute mean wind. Category 4 corresponds to 160–199 km/h mean wind and indicative maximum gusts of 225–279 km/h. Categories 3 through 5 are called severe tropical cyclones. These thresholds differ from the U.S. Saffir-Simpson hurricane scale, which uses one-minute sustained wind, so matching category numbers across the two systems can be misleading. [2][3]

Alfred developed from Tropical Low 22U northeast of Cooktown and was named on February 23. It strengthened while moving over the Coral Sea and reached category 4 on February 27 UTC, remaining at its peak for about 18 hours in the Bureau’s local-time chronology. From March 1, a less favorable environment caused weakening. By March 2 it was category 1 and still far east of the Queensland coast. [1][4]

The storm then changed structure and direction. Alfred briefly regained category 2 strength, interacted with the subtropical jet and was classified as a subtropical cyclone on March 3. It turned sharply west on March 4, and renewed tropical organization led the Bureau to classify it again as a category 1 tropical cyclone late on March 5 and category 2 early on March 6. Its slow and sometimes erratic westward motion lengthened the coastal impact period. [1][4]

Alfred weakened to category 1 on March 7, crossed Moreton Island around 1 a.m. AEST on March 8 and dropped below tropical-cyclone strength a few hours later. The circulation stalled near Bribie Island, again showed subtropical characteristics, crossed Bribie Island that evening and moved onto the mainland around 9 p.m. The accurate shorthand is therefore: category 4 peak offshore, category 1 at Moreton Island, and below tropical-cyclone strength before the mainland crossing. [1][2][4]

The lower category near land did not make the event harmless. Alfred produced damaging gusts, widespread power outages, flooding rain, very large waves and severe coastal erosion across southeast Queensland and northeast New South Wales. The Bureau recorded a 120 km/h gust at Cape Byron and 275.2 mm in one day at Brisbane’s official gauge. More than 500,000 customers lost power, and some beaches lost millions of cubic metres of sand. [1][2]

Cyclone category describes wind intensity near the center, not the total severity of rain, flood, waves or storm tide. The Bureau explicitly warns that even category 1 systems and downgraded tropical lows can cause dangerous flooding and coastal impacts. For historical comparisons, readers should specify the time and location attached to a category claim and use the final Bureau analysis rather than a single live forecast issued while Alfred was evolving. [1][3][5]

Sources

  1. Australian Bureau of Meteorology: Severe Tropical Cyclone Alfred (22U)
  2. Australian Bureau of Meteorology: 2024–25 Northern Wet Season
  3. Australian Bureau of Meteorology: Tropical Cyclone Categories
  4. Australian Bureau of Meteorology: Tropical Climate Update, 11 March 2025
  5. Australian Bureau of Meteorology: What Is a Tropical Cyclone?

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