Lably
Skip to content

Cyclone Val

South Pacific cyclone in 1991

  • 11 min read
  • 3 chapters

Explore on Lably

ToursExplore Lably’s 3D tours

On December 9, Val completed its loop and started to move eastwards and gradually weakened before it passed over American Samoa early the next day. After passing over American Samoa, Val appeared to threaten the Southern Cook Islands and was expected to pass close to Palmerston Island. However, as the system continued to weaken, it started to move more towards the south-southeast than had been expected, which spared the Cook Islands. During December 13, Val became a strong extratropical depression, before the system was captured and sheared apart by strong environmental westerlies associated with the Antarctic Circumpolar Current as it approached 50°S during December 16.

The cyclone lasted for five days in American Samoa and was designated by the United States Government as a major disaster on December 13, 1991. Western Samoa suffered more damage than American Samoa. The cyclone devastated the islands with 150-mile-per-hour (240 km/h) winds and 50-foot (15 m) waves. The overall damages caused by Cyclone Val in American Samoa have been variously assessed. One estimate put the damages at $50 million in American Samoa and $200 million in Western Samoa due to damage to electrical, water, and telephone connections and destruction of various government buildings, schools, and houses.

Meteorological history

During the opening days of December 1991, the Fiji Meteorological Service (FMS) started to monitor a small circulation, that had developed along the Intertropical Convergence Zone, just to the north of Tokelau as a result of a surge within the westerlies. Over the next few days, the system moved westwards towards Rotuma and Tuvalu, where it lay near the centre of an area of upper level outflow. During December 4, the FMS classified the system as a tropical depression by the FMS, while it was located just to the southeast of Tuvalu and moving north-westwards. The system was then named Val by the FMS during the next day, after it had become a category 1 tropical cyclone on the Australian tropical cyclone intensity scale. During that day the United States Naval Western Oceanography Center (NWOC) designated the system as Tropical Cyclone 06P and started to issue advisories, while Val started to move towards the south-southeast, after the upper level north-westerly steering winds increased. During December 6, the NWOC reported that the system had become equivalent to a category 2 hurricane on the Saffir-Simpson hurricane scale as Val continued to steadily intensify and moved south-eastwards, away from Tuvalu and towards the Samoan Islands. Early on December 7, the FMS reported that the system had become a category 3 severe tropical cyclone, as it started to be steered southwards by upper-level northerlies.

Later that day, the FMS reported that Val had reached its peak 10-minute sustained wind speeds of about 165 km/h (105 mph), which made it a category 4 severe tropical cyclone on the Australian scale. The system subsequently made landfall on the Samoan island of Savaii at around 1800 UTC (07:00 SST), while the NWOC reported that the cyclone had peaked with 1-minute sustained wind speeds of about 230 km/h (145 mph), which made it equivalent to a category 4 hurricane on the SSHWS. After Val had passed over the island, weakening upper-level winds caused the system to slow down before it made a sharp clockwise loop which almost brought it over Savaii for a second time. During December 9, Val completed its loop and started to move eastwards and gradually weaken, before it passed over the American Samoan island of Tutuila early the next day. After passing over American Samoa, Val appeared to threaten the Southern Cook Islands and was expected to pass close to Palmerston Island. However, as the system continued to weaken, it started to move more towards the south-southeast then had been expected, which spared the Cook Islands. During December 12, the FMS reported that Val had weakened into a category two tropical cyclone and passed the primary warning responsibility for the system to the New Zealand Meteorological Service (NZMS) after Val had moved out of its area of responsibility. Shortly after moving into the NZMS's area of responsibility, Val transitioned into a strong extratropical depression. Storm force winds subsequently persisted around the centre of Val's extratropical remnants for the next 3 days, before the system was captured and sheared apart by strong environmental westerlies associated with the Antarctic Circumpolar Current as it approached 50°S.

Sign in to keep reading

2 more chapters are free with a Lably account.

More in Earth science