1970 Western Pacific typhoon season
Typhoon Olga 1970
Typhoon Olga reached exceptional intensity over the Philippine Sea before weakening on its approach to Japan in July 1970. Heavy rain caused deadly flooding and landslides even after the storm's winds had fallen far below their offshore peak.
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161 mph
Jul 1, 1970 during the tropical stage
Full archive record, including non-tropical stages if present
Along the recorded center positions
STORM HISTORY
Rapid development in the Philippine Sea
Olga began as a tropical wave near the Marshall Islands. Strong easterly winds carried it west through the Caroline Islands, and a closed circulation organized south of Guam. As steering winds weakened, Olga slowed, turned northwest and intensified rapidly.
The archive records peak one-minute winds of 140 kt on 1 July. Olga then moved north through a break in the subtropical ridge. It weakened east of Taiwan as drier air entered the circulation and its track bent toward Japan.
Rain in Japan and South Korea
Olga reached Japan's Kansai region south of Osaka on 5 July as a tropical storm. Rainfall reached about 14 inches in some places, producing landslides and extensive flooding. Twenty deaths were reported in Japan.
After entering the Sea of Japan, the circulation merged with a cold front. Heavy rainfall associated with Olga's remnants also affected South Korea, where 29 deaths were reported. The archived track continues through 7 July.
Further reading
QUICK ANSWERS
Olga in brief
What was Typhoon Olga's highest wind speed?
161 mph, the highest one-minute sustained wind in its tropical stage, recorded on Jul 1, 1970, 12:00 PM UTC.
What category was Typhoon Olga?
Category 5 at its peak on the Saffir–Simpson one-minute wind scale, first reaching Category 5 on Jul 1, 1970, 09:00 AM UTC. Other agencies classify storms differently.
What was Typhoon Olga's lowest pressure?
905 mb, the minimum central pressure recorded during its tropical stage, on Jul 1, 1970, 06:00 AM UTC.
When did Typhoon Olga occur?
The archived track runs from Jun 26, 1970, 12:00 PM UTC to Jul 7, 1970, 06:00 AM UTC, with the tropical stage from Jun 28, 1970, 06:00 AM UTC to Jul 5, 1970, 09:00 PM UTC.
Where did Typhoon Olga form?
In the Western Pacific basin, in the 1970 season. Its first archived position is 7°N, 153.4°E on Jun 26, 1970, 12:00 PM UTC.
Did Typhoon Olga make landfall?
The archive places its center over land at 2 recorded positions; the strongest is 58 mph on Jul 5, 1970, 12:00 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