WESTERN PACIFIC · 1970 SEASON
Typhoon Joan (1970)
Recorded track and intensity · 9 Oct 1970–18 Oct 1970
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Wind speed & pressure
13 Oct, 00:00 UTCForward speed & ACE
13 Oct, 00:00 UTCHover or tap either graph to follow the track. The slider controls both graphs. Each line uses its matching colored axis.
Forward speed measures the center’s motion. ACE accumulates squared one-minute winds at 00, 06, 12 and 18 UTC during tropical or subtropical stages at 34 kt or above. Missing observations make ACE partial. Missing measurements remain gaps.
173 mph / 278 km/h
12 Oct 1970 · tropical stage
Full archive record, including non-tropical stages if present
Along the recorded center positions
STORM HISTORY
Track and intensity summary
Joan is listed in the Western Pacific basin for the 1970 season. Its archived track begins on 9 Oct 1970, 00:00 UTC at 7.6°N, 147°E. US-agency wind is not available for this first observation. These dates describe the available observations, which may include stages before and after the tropical cyclone phase.
The first Category 5 observation appears on 12 Oct 1970, 18:00 UTC. The highest recorded tropical-stage one-minute sustained wind is 150 knots (173 mph / 278 km/h), first recorded on 13 Oct 1970, 00:00 UTC at 13.3°N, 124.7°E. The minimum recorded tropical-stage central pressure is 905 hPa on 12 Oct 1970, 18:00 UTC.
The full record spans 234 hours and approximately 4,810 kilometers along the recorded center positions. The last recorded position is 21.2°N, 111.6°E on 18 Oct 1970, 18:00 UTC. The final tropical-stage observation is earlier, on 18 Oct 1970, 03:00 UTC.
This summary is calculated from the NOAA IBTrACS archive. Category 5 describes the storm’s peak recorded wind intensity, not its intensity at landfall or the severity of impacts at any location. Landfall times, damage and casualties have not been independently reviewed for this page.
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 · Field documentation
Sources & methodology