Typhoon Nora, known in the Philippines as Typhoon Luming, was the fourth-most intense tropical cyclone on record. Originating from an area of low pressure over the western Pacific, Nora was first identified as a tropical depression on October 2, 1973. Tracking generally westward, the system gradually intensified, attaining typhoon status the following evening. After turning northwestward, the typhoon underwent a period of rapid intensification, during which its central pressure decreased by 77 mb (hPa; 2.27 inHg) in 24 hours. At the end of this phase, Nora peaked with winds of and a pressure of 875 mb (hPa; 25.91 inHg), making it the most-intense tropical cyclone on record (alongside Typhoon Ida in 1958) at the time; however, this pressure has since been surpassed by Typhoon June, Typhoon Tip and Hurricane Patricia. The typhoon subsequently weakened and turned northwestward as it approached the Philippines. After brushing Luzon on October 7, the system passed south of Taiwan and ultimately made landfall in China on October 10. Once onshore, Nora quickly weakened and dissipated the following day.
The Philippines and Taiwan sustained the most extensive losses from Typhoon Nora, with 36 people losing their lives collectively. In the former, more than 1 million residents were left homeless as high winds and flooding wrecked homes. Damage in the country reached $2 million (1973 USD). In Taiwan, more than 1,000 homes were destroyed and 8,000 people were left homeless. The typhoon was also responsible for several maritime incidents that killed at least four people.
Meteorological history
On September 30, a weak surface low developed within the monsoon trough about 195 km (120 mi) south of Yap. Drifting northwestward, the system gradually organized into a tropical depression by October 2. Later that day, aircraft reconnaissance revealed the system to have intensified into a tropical storm, at which time it was assigned the name Nora. The system's movement soon became slow and erratic, with Nora executing a counter-clockwise loop on October 3. After completing the loop, it attained typhoon status and acquired a temporary northward trajectory. Due to the cyclone's proximity to the Philippines, the Philippine Atmospheric, Geophysical and Astronomical Services Administration also monitored the storm and assigned it with the local name Luming. Late on October 4, Nora began to undergo a period of rapid intensification. Several aircraft reconnaissance missions were flown by the U.S. Air Force 54th Weather Reconnaissance Squadron into the storm between October 5 and 6, documenting the typhoon's dramatic strengthening.
By the evening of October 5, Nora had attained winds in excess of , ranking it as a Category 5-equivalent super typhoon on the Saffir–Simpson hurricane scale. A recon mission into the storm at this time revealed concentric eyewalls, measured at and . Initially, the aircraft was unable to penetrate into the core of the eye due to severe turbulence; however, they were successful after a second attempt. Once inside the eye, they discovered an almost cloud-free center with "an amphitheater or bowl-like appearance." Stratocumulus clouds were suppressed to an unusually low altitude of . The core of Nora was exceptionally warm, with temperatures reaching a near-record at the 700 mb level. At 0020 UTC on October 6, a dropsonde released by the reconnaissance team recorded a surface pressure of 877 mb (hPa; 25.91 inHg) just inside the eyewall of the typhoon. At this time, maximum winds were estimated to have peaked at . This intensity ranked Nora as the most-intense tropical cyclone on record in the world, alongside Typhoon Ida in 1958. However, in post-storm analysis, it was noted that since the dropsonde did not record a pressure at the storm's center, Nora was likely slightly stronger than indicated. Since then, Nora's intensity has been surpassed by three other storms: Typhoon June in 1975, Typhoon Tip in 1979, and Hurricane Patricia in 2015.