1997 Western Pacific typhoon season
Typhoon Isa 1997
Typhoon Isa opened the western Pacific's series of super typhoons in 1997. It damaged crops and power lines in Micronesia, while an outer rainband brought Guam heavy rain during the island's dry season.
Drag to pan. Pinch or Ctrl/⌘ + scroll to zoom. Keyboard: plus or minus to zoom, arrow keys to pan, and 0 to show the full track.
167 mph
Apr 20, 1997 during the tropical stage
Full archive record, including non-tropical stages if present
Along the recorded center positions
STORM HISTORY
A slow start near Pohnpei
Isa developed within the monsoon trough near the Caroline Islands in April. The broad circulation drifted and looped before turning west under a ridge to its north. As a tropical storm near Pohnpei, it brought winds that downed trees and damaged power lines. About 15 percent of the island's crops suffered damage, including banana and breadfruit.
Rain south of Guam
The typhoon remained about 260 kilometers south of Guam, but one of its rainbands stalled across the island. Rainfall reached roughly 15 to 25 centimeters, with gusts and scattered power failures. Wind and sea salt damaged vegetable crops. The storm threat also delayed the final flight carrying Kurdish refugees from Guam during Operation Pacific Haven.
A large eye at peak strength
Isa turned north through a weakness in the subtropical ridge and reached peak one-minute winds of 145 kt on April 20. Near its peak, it had a large eye and few spiral rainbands, an annular structure. The typhoon then weakened and accelerated northeast before merging with a larger extratropical cyclone east of Japan on April 24. No deaths were attributed to Isa in the saved account.
Further reading
QUICK ANSWERS
Isa in brief
What was Typhoon Isa's highest wind speed?
167 mph, the highest one-minute sustained wind in its tropical stage, recorded on Apr 20, 1997, 12:00 AM UTC.
What category was Typhoon Isa?
Category 5 at its peak on the Saffir–Simpson one-minute wind scale, first reaching Category 5 on Apr 19, 1997, 03:00 PM UTC. Other agencies classify storms differently.
What was Typhoon Isa's lowest pressure?
940 mb, the minimum central pressure recorded during its tropical stage, on Apr 20, 1997, 12:00 AM UTC.
When did Typhoon Isa occur?
The archived track runs from Apr 9, 1997, 12:00 AM UTC to Apr 24, 1997, 12:00 PM UTC, with the tropical stage from Apr 12, 1997, 06:00 AM UTC to Apr 23, 1997, 03:00 PM UTC.
Where did Typhoon Isa form?
In the Western Pacific basin, in the 1997 season. Its first archived position is 6.2°N, 153°E on Apr 9, 1997, 12:00 AM UTC.
Did Typhoon Isa make landfall?
No archived position places Typhoon Isa's center over land, but positions are six-hourly and a brief landfall can fall between them.
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