Super Typhoon Nancy, also known as the 2nd Muroto Typhoon (第二室戸台風, Daini-muroto Taifū), was an extremely powerful tropical cyclone of the 1961 Pacific typhoon season, produced the highest accumulated cyclone energy—a metric used to measure the total energy generated by tropical cyclones—of any individual cyclone on record in the basin, also one of the most intense tropical cyclones on record. The system possibly had the strongest winds ever measured in a tropical cyclone, with 345 km/h (215 mph) winds, tied with Hurricane Patricia of 2015. Nancy caused extensive damage, as well as at least 202 deaths and nearly 5,000 injuries in Japan and elsewhere, in September 1961.
Meteorological history
A tropical depression formed from a low-pressure area near Kwajalein Atoll on September 7. It strengthened rapidly; by the time position fixes could be taken, Nancy was nearly a super typhoon, on September 8. Moving gradually westward, Nancy explosively deepened and reached wind speeds equivalent to a Category 5 super typhoon (Saffir–Simpson Hurricane Scale) on September 9. It would maintain that intensity for the next several days.
On September 12, the storm reached its peak intensity with a possible 345 km/h (215 mph). However, older measurements were unreliable, so it was most likely weaker.
Shortly after reaching peak intensity, Nancy approached the Ryūkyū Islands and began turning. It passed near Okinawa and over Naze. The ridge steering Nancy broke down, and the typhoon turned sharply and headed towards Japan. Nancy made landfall as a strong typhoon on September 16 as it passed directly over Cape Muroto. Nancy made a second landfall on Honshū near Osaka. The typhoon rapidly traveled up the length of the island as it continued accelerating, eventually reaching a forward speed of 105 km/h; 56 kn (65 mph). The typhoon quickly crossed over Hokkaidō before entering the Sea of Okhotsk as a tropical storm. Nancy went extratropical on September 17. The extratropical system eventually crossed over Kamchatka and entered the open ocean.
Impact
Although there is no damage total known for Nancy, damage was "phenomenal" according to the JMA. There were at least 194 deaths and eight people unaccounted for, according to the Japanese government.
Guam
On Guam, over half of all crops were destroyed by heavy winds and rain. A total of $40,000 (1961 USD) worth of damage was done to roads on the island. Most of the damage was on the southern end of the island. No deaths were reported on Guam.
Ryukyu Islands
On Okinawa, low-lying areas experienced heavy flooding, which did significant damage to agriculture and structures.
Japan
In Japan, according to Japan Fire and Disaster Management Agency official confirmed report, 194 people were killed, 8 were missing, and 4,972 people were injured. These totals made Nancy the sixth-deadliest typhoon to hit Japan at the time. Timely warnings and adequate preparations were probably responsible for the relatively low death toll. The damage was "small" relative to other typhoons that impacted densely populated areas of Japan.
Hundreds of thousands of people had their lives disrupted. Super Typhoon Nancy destroyed 11,539 houses, damaged 32,604 homes, and flooded 280,078 others. Although the exact number may never be known, the Stars and Stripes reported in late September 1961 that over 1,056 ships and fishing vessels were sunk or blown ashore, and that many more were damaged.
Floodwaters washed away 566 bridges and caused 1146 landslides. Roads were destroyed at a total of 2,053 locations. Damages in Osaka amounted to US$0.5 billion.
On Amami Ōshima, one person was missing and another was badly injured. A ship was sunk. Extensive flooding of crops and houses left 152 people homeless.
Due to Nancy's damage and death toll, the Japan Meteorological Agency named Nancy the "Second Muroto Typhoon". Nancy is one of only twelve typhoons to receive special names in Japan.
Records
A reconnaissance aircraft flying into the typhoon near its peak intensity on September 12 determined Nancy's one-minute sustained winds to be 185 knots (213 mph; 343 km/h). If these values are reliable, they would be the highest wind speeds ever measured in a tropical cyclone. However, it was later determined that measurements and estimations of wind speeds from the 1940s to 1960s were excessive. Thus, Nancy's winds may actually be lower than its official best-track value, which may actually be closer to 153 knots (285 km/h; 175 mph). In 2016, reanalysis of Hurricane Patricia noted that the storm had the same sustained winds as Nancy, the highest on record in the Western Hemisphere.
Although the Saffir–Simpson hurricane wind scale (SSHWS) did not exist at the time, Nancy would have been a Category 5 equivalent for a total of five and a half days (or 132 hours), assuming the wind speed data is reliable. If so, this is the record for the Northern Hemisphere and more than a day longer than the runner-up system, 1962's Typhoon Karen.