1951 Western Pacific typhoon season
Typhoon Iris 1951
Typhoon Iris swept through the Philippines in May 1951, damaging crops and transport links before regaining strength over the South China Sea. Its journey carried it from the waters east of Chuuk to the Pacific beyond Japan, with a Category 5 peak east of the Philippines and a later turn past the Ryukyu Islands.
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173 mph
May 3, 1951 during the tropical stage
Full archive record, including non-tropical stages if present
Along the recorded center positions
STORM HISTORY
Reconnaissance and the approach to the Philippines
Iris developed from a tropical wave east of Chuuk in late April. A ship's report of strong winds prompted the Guam Fleet Weather Center to send reconnaissance aircraft into the developing cyclone. The archive begins on 28 April and places Iris in its tropical stage from 29 April, as it moved west across the Philippine Sea.
Iris reached Category 5 strength at 18:00 UTC on 3 May. Six hours later, US-agency one-minute wind estimates peaked at 150 kt east of the Philippines. The archive's minimum pressure of 909 hPa first appears at 12:00 UTC on 3 May, before the strongest winds.
Rain and damage across the islands
Iris weakened while crossing the Philippine archipelago. The historical account records nine deaths and 39 injuries, with damage to highways, bridges and crops estimated at 19.2 million Philippine pesos, about US$9.5 million at the time. Gandara on Samar recorded 484.4 mm of rain, while nearby Catbalogan reported winds of 155 km/h.
The sampled track places Iris's center over land with winds of 95 kt late on 4 May and 55 kt on 6 May. After crossing the islands, Iris entered the South China Sea as a tropical storm and turned north west of Luzon.
Renewed strength and a looping finish
Iris regained typhoon-strength winds by 7 May. It passed south of Taiwan and accelerated northeast through the Ryukyu region, reaching 85 kt in the archive on 9 May. The storm then weakened over the ocean south of Japan.
On 11 May, Iris turned back west before curving north and resuming an eastward course. Tropical-stage observations end that morning, while the complete archive continues to 14 May. By the end of the storm, Guam forecasters had issued 50 tropical cyclone bulletins and reconnaissance crews had obtained 54 fixes, records for the Fleet Weather Center at the time.
Further reading
QUICK ANSWERS
Iris in brief
What was Typhoon Iris's highest wind speed?
173 mph, the highest one-minute sustained wind in its tropical stage, recorded on May 4, 1951, 12:00 AM UTC.
What category was Typhoon Iris?
Category 5 at its peak on the Saffir–Simpson one-minute wind scale, first reaching Category 5 on May 3, 1951, 06:00 PM UTC. Other agencies classify storms differently.
What was Typhoon Iris's lowest pressure?
909 mb, the minimum central pressure recorded during its tropical stage, on May 3, 1951, 12:00 PM UTC.
When did Typhoon Iris occur?
The archived track runs from Apr 28, 1951, 12:00 PM UTC to May 14, 1951, 06:00 PM UTC, with the tropical stage from Apr 29, 1951, 12:00 AM UTC to May 11, 1951, 09:00 AM UTC.
Where did Typhoon Iris form?
In the Western Pacific basin, in the 1951 season. Its first archived position is 6.3°N, 144.9°E on Apr 28, 1951, 12:00 PM UTC.
Did Typhoon Iris make landfall?
The archive places its center over land at 2 recorded positions; the strongest is 109 mph on May 4, 1951, 09:00 PM UTC. Positions are six-hourly, so this is not a landfall chronology.
METHODOLOGY
Data sources and limitations
The map and summary are generated from NOAA's IBTrACS v04r01 archive. Wind and category use US-agency records; minimum pressure is calculated during the tropical stage, with the archive's pressure source retained. Category 5 refers to the Saffir–Simpson one-minute wind scale; local agencies may use different classifications. Coastlines use Natural Earth's 1:10m land data.
Track distance adds great-circle distances between consecutive observations, excluding gaps over 12 hours. This track has no gaps over 12 hours. The line shows the storm's center, not its size, rainfall or flood extent. Converted wind speeds are rounded to the nearest whole unit.
Archive retrieved
NOAA IBTrACS archive and Field documentation
Sources & methodology