Two separate world records for tropical cyclones, one for sheer intensity and one for physical size, both belong to the same storm. Typhoon Tip spent barely two days at its peak in October 1979, largely over open ocean, far from any populated coastline, and in that short window set marks that have stood for close to half a century.
The most intense: 870 hectopascals
On 12 October 1979, Typhoon Tip's central pressure dropped to 870 hectopascals, the lowest sea-level pressure ever measured anywhere on Earth, tropical cyclone or otherwise. Lower central pressure means a steeper pressure gradient around the storm's centre, which is what drives a cyclone's wind speed, and Tip's peak sustained winds reached around 305 km/h. For comparison, a strong Category 5 hurricane in the Atlantic typically bottoms out somewhere in the 900s hPa range; Tip was roughly 30 to 40 hectopascals lower than that, a genuinely enormous margin in tropical cyclone terms.
The largest: a wind field bigger than half the continental United States
Tip's size was, if anything, even more remarkable than its intensity. At its peak, the storm's gale-force wind field, measured out to where sustained winds drop below 63 km/h, stretched roughly 2,220km (1,380 miles) across, nearly double the diameter of the previous largest storm on record, Typhoon Marge in 1951. That's an area of circulating wind and cloud comparable to roughly half the width of the continental United States, or more than half the east-to-west span of mainland Australia. The scale was significant enough that the storm was tracked by around 60 separate reconnaissance missions, making it one of the most thoroughly observed cyclones in history.
Despite holding both records simultaneously, and remaining the most intense tropical cyclone ever measured to this day, Tip's death toll was comparatively limited, under 100 people, largely because its most extreme intensity was reached and spent almost entirely over open Pacific water. By the time it weakened and made landfall in Japan in mid-October, it had dropped to a much less extreme storm, though it still caused significant flooding and wind damage.
Where Australia's cyclones sit
Australia's own cyclone records don't come close to Tip's numbers, but two storms in particular stand out for different reasons.
Cyclone Tracy, which struck Darwin on Christmas Day 1974, was a comparatively small and, by world standards, moderately intense storm, with gale-force winds extending only about 40-50km from its centre and a central pressure of 950 hPa, nowhere near Tip's 870. What made Tracy devastating wasn't its intensity relative to the biggest storms on Earth, it was that a storm of that size hit a city directly: wind gusts reached 217 km/h before the airport's anemometer was destroyed, some estimates suggest gusts may have reached as high as 280 km/h during the peak, and more than 70% of Darwin's buildings were destroyed. Sixty-six people were killed and around 30,000 residents were evacuated from a city of roughly 47,000.
Cyclone Mahina, which struck far north Queensland in March 1899, is a harder storm to pin down precisely, and that uncertainty is itself part of the story. Its estimated central pressure of around 880 to 914 hPa would make it a strong contender for the most intense cyclone ever recorded in the Southern Hemisphere, rivalling storms far more recent and far better measured. Mahina is also associated with the deadliest natural disaster in Australian history, killing somewhere between 300 and 410 people, most of them pearling crews caught at sea off Bathurst Bay. The storm surge it produced is where the real uncertainty lies: contemporary accounts describe a surge as high as 13 to 15 metres, which would be the largest ever recorded anywhere on Earth, but more recent scientific modelling based on the storm's official pressure reading suggests a surge closer to 2 to 3 metres is more physically plausible. Both figures are still cited today, and the true number likely sits somewhere in a very wide range that 1899-era observation simply wasn't equipped to pin down with confidence.