Typhoon Ragasa underwent rapid intensification late last week and became the first super typhoon so far this season in the Northwest Pacific region.

As Super Typhoon Ragasa approached Babuyan Island on Monday, it was a colossal system with an eye measuring 40 nautical miles (74 km) in diameter and peak wind gusts of around 175 knots (324 km/h) near its core. For comparison, Tropical Cyclone Yasi’s peak wind gusts were around 285 km/h.

Severe Tropical Cyclone Yasi (/ˈjɑːsiː/) was a powerful and destructive tropical cyclone that made landfall in northern Queensland, Australia in early 2011, causing major damage to the affected areas. Originating as a tropical low near Fiji on 26 January, the system intensified to tropical cyclone status during the evening of 30 January. Yasi deepened rapidly over the next 24 hours, and was classified as a Category 3 cyclone at about 5 PM AEST (07:00 UTC) on 31 January 2011.[1] Late on 1 February, the cyclone strengthened to a Category 4 system; then, early on 2 February, the cyclone intensified into a Category 5 Severe Tropical Cyclone.[2] The system had a well-defined eye and continued to track west-southwestward, maintaining a central pressure of 930 hPa

One of the standout features in the satellite images of Ragasa is the presence of mesovortices, which are small-scale circulations of air near the typhoon’s eyewall. Mesovortices can only be seen in satellite images when the eye is clear of high cloud, which is a sign of a mature and powerful typhoon.

Mesovortices in the eye of a typhoon can be extremely dangerous as they are capable of producing very destructive winds. The strongest wind gust ever reliably measured on Earth was 220 knots (407 km/h) in the eyewall of Tropical Cyclone Olivia in 1996 over Australia’s Barrow Island. This gust is believed to have been associated with a mesovortex.