This is storm RUBY that was active in 1964 in the W. Pacific region with maximum winds of 222 km/h.

What was the maximum intensity of the storm?

Max Wind: 222 km/h. Min Pressure: hPa.

storm RUBY (1964) - Track and intensity details

Name: storm RUBY
Start: 1964-09-01
End: 1964-09-06
Location: W. Pacific

RUBY (1964)

Storm Code: 1964245N20132 | Region: W. Pacific
Active from 01/09/1964 to 06/09/1964 (6 days)

222 km/h

1-min Wind (JTWC)

Level 17

194 km/h

10-min Wind (HKO)

Level 16

960 hPa

Min Pressure

3,137 km

Distance

Forecast Agencies

Agency	Max Intensity	Trajectory	Energy	highest_classification
JTWC	222	~	43	3,137	77.65	123.93	Level 17 - Super Typhoon
CMA (China)	161	960	41	2,424	49.05	63.71	Level 14 - Violent Storm
HKO (Hong Kong)	194	960	39	2,337	66.95	98.52	Level 16 - Super Typhoon
DS824	222	~	43	3,137	77.65	123.93	Level 17 - Super Typhoon
TD9635	222	963	37	2,300	76.73	123.29	Level 17 - Super Typhoon
WMO (International) (coordinates_only)	~	970	20	2,566	~	~	Undefined
JMA (Japan) (coordinates_only)	~	970	39	2,502	~	~	Undefined
TD9636	213	~	33	2,015	70.28	110.34	Level 17 - Super Typhoon

Agency

Max Intensity

Trajectory

Energy

highest_classification

Max Wind (km/h)

Min Pressure (hPa)

Number of points

Distance (km)

ACE (10⁴ (km/h)²)

PDI (10⁶ (km/h)³)

JTWC

222

3,137

77.65

123.93

Level 17 - Super Typhoon

CMA (China)

161

960

2,424

49.05

63.71

Level 14 - Violent Storm

HKO (Hong Kong)

194

960

2,337

66.95

98.52

Level 16 - Super Typhoon

DS824

222

3,137

77.65

123.93

Level 17 - Super Typhoon

TD9635

222

963

2,300

76.73

123.29

Level 17 - Super Typhoon

WMO (International)
(coordinates_only)

970

2,566

Undefined

JMA (Japan)
(coordinates_only)

970

2,502

Undefined

TD9636

213

2,015

70.28

110.34

Level 17 - Super Typhoon

Advanced Meteorological Indices by Agency Automatically calculated from raw data

JTWC

Energy
ACE (10⁴ (km/h)²)	77.65	Very High
PDI (10⁶ (km/h)³)	123.93
Intensification / Weakening
Max Wind Gain/Step	+9 km/h
Max Wind Gain/24h	+37 km/h	Fast
Max Wind Loss/Step	-37 km/h
Movement & Duration
Avg Movement Speed	24.9 km/h
Tracking Time	126h (5.3 days)
Time as TD+ (≥34kt)	234h (9.8d)
Time as Storm+ (≥64kt)	162h (6.8d)
Peak Intensity & Range
Peak Intensity	14:00 05/09/1964 22.3°N, 113.7°E
Latitude	19.2°N – 28.2°N (9°)
Longitude	105.8°E – 132.2°E (26.4°)

CMA (China)

Energy
ACE (10⁴ (km/h)²)	49.05	High
PDI (10⁶ (km/h)³)	63.71
Intensification / Weakening
Max Wind Gain/Step	+19 km/h
Max Wind Gain/24h	+54 km/h	Fast
Max Wind Loss/Step	-28 km/h
Pressure Variation
Max Pressure Drop/Step	-5 hPa
Max Pressure Drop/24h	-14 hPa
Max Pressure Rise/Step (weakening)	+10 hPa
Movement & Duration
Avg Movement Speed	20.2 km/h
Tracking Time	120h (5 days)
Time as TD+ (≥34kt)	198h (8.3d)
Time as Storm+ (≥64kt)	114h (4.8d)
Peak Intensity & Range
Peak Intensity	02:00 05/09/1964 20.8°N, 116.1°E
Latitude	19.1°N – 24.6°N (5.5°)
Longitude	109.5°E – 131°E (21.5°)

HKO (Hong Kong)

Energy
ACE (10⁴ (km/h)²)	66.95	Very High
PDI (10⁶ (km/h)³)	98.52
Intensification / Weakening
Max Wind Gain/Step	+9 km/h
Max Wind Gain/24h	+37 km/h	Fast
Max Wind Loss/Step	-28 km/h
Pressure Variation
Max Pressure Drop/Step	-3 hPa
Max Pressure Drop/24h	-10 hPa
Max Pressure Rise/Step (weakening)	+10 hPa
Movement & Duration
Avg Movement Speed	20.5 km/h
Tracking Time	114h (4.8 days)
Time as TD+ (≥34kt)	222h (9.3d)
Time as Storm+ (≥64kt)	156h (6.5d)
Peak Intensity & Range
Peak Intensity	08:00 05/09/1964 21.3°N, 115°E
Latitude	19.1°N – 23.1°N (4°)
Longitude	110.8°E – 131.9°E (21.1°)

DS824

Energy
ACE (10⁴ (km/h)²)	77.65	Very High
PDI (10⁶ (km/h)³)	123.93
Intensification / Weakening
Max Wind Gain/Step	+9 km/h
Max Wind Gain/24h	+37 km/h	Fast
Max Wind Loss/Step	-37 km/h
Movement & Duration
Avg Movement Speed	24.9 km/h
Tracking Time	126h (5.3 days)
Time as TD+ (≥34kt)	234h (9.8d)
Time as Storm+ (≥64kt)	162h (6.8d)
Peak Intensity & Range
Peak Intensity	14:00 05/09/1964 22.3°N, 113.7°E
Latitude	19.2°N – 28.2°N (9°)
Longitude	105.8°E – 132.2°E (26.4°)

TD9635

Energy
ACE (10⁴ (km/h)²)	76.73	Very High
PDI (10⁶ (km/h)³)	123.29
Intensification / Weakening
Max Wind Gain/Step	+9 km/h
Max Wind Gain/24h	+37 km/h	Fast
Max Wind Loss/Step	-37 km/h
Pressure Variation
Max Pressure Drop/Step	-4 hPa
Max Pressure Drop/24h	-16 hPa
Max Pressure Rise/Step (weakening)	+1 hPa
Movement & Duration
Avg Movement Speed	21.3 km/h
Tracking Time	108h (4.5 days)
Time as TD+ (≥34kt)	222h (9.3d)
Time as Storm+ (≥64kt)	162h (6.8d)
Peak Intensity & Range
Peak Intensity	14:00 05/09/1964 22.3°N, 113.7°E
Latitude	19.2°N – 23.6°N (4.4°)
Longitude	111.6°E – 132.2°E (20.6°)

WMO (International)

Pressure Variation
Max Pressure Drop/Step	-10 hPa
Max Pressure Drop/24h	-26 hPa	Strong
Max Pressure Rise/Step (weakening)	+10 hPa
Movement & Duration
Avg Movement Speed	22.5 km/h
Tracking Time	114h (4.8 days)
Peak Intensity & Range
Latitude	19.2°N – 25.7°N (6.5°)
Longitude	108°E – 130.6°E (22.6°)

JMA (Japan)

Pressure Variation
Max Pressure Drop/Step	-5 hPa
Max Pressure Drop/24h	-17 hPa
Max Pressure Rise/Step (weakening)	+5 hPa
Movement & Duration
Avg Movement Speed	21.9 km/h
Tracking Time	114h (4.8 days)
Peak Intensity & Range
Latitude	19°N – 25.2°N (6.2°)
Longitude	109.5°E – 130.5°E (21°)

TD9636

Energy
ACE (10⁴ (km/h)²)	70.28	Very High
PDI (10⁶ (km/h)³)	110.34
Intensification / Weakening
Max Wind Gain/Step	+9 km/h
Max Wind Gain/24h	+37 km/h	Fast
Max Wind Loss/Step	-17 km/h
Movement & Duration
Avg Movement Speed	21 km/h
Tracking Time	96h (4 days)
Time as TD+ (≥34kt)	198h (8.3d)
Time as Storm+ (≥64kt)	156h (6.5d)
Peak Intensity & Range
Peak Intensity	08:00 05/09/1964 21.9°N, 114.9°E
Latitude	19.2°N – 22.8°N (3.6°)
Longitude	112.6°E – 130.8°E (18.2°)

Advanced Indices Legend

ACE: Accumulated Cyclone Energy - measures total storm activity

PDI: Power Dissipation Index - measures potential destructiveness

RI: Rapid Intensification - when wind increases >=30 kt/24h or pressure drops >=30 hPa/24h

Countries with Direct Landfall

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Index	Meaning	Formula / Condition	Classification
ACE Accumulated Cyclone Energy	Accumulated Cyclone Energy. Measures the total energy generated by the storm during its lifetime. Only counts reports with wind ≥ 35 kt (TS level or higher).	`ACE = Σ(V_max²) / 10&sup4;` Unit: 10⁴ kt²	< 2: Low 2-6: Medium 6-15: High ≥ 15: Very High
PDI Power Dissipation Index	Power Dissipation Index. More sensitive than ACE to extremely strong storms due to using cubic power. Reflects potential destructive power.	`PDI = Σ(V_max&sup³;) / 10&sup6;` Unit: 10⁶ kt³	Higher value = greater cumulative destructive power
RI Rapid Intensification	Rapid Intensification - storm strengthens suddenly in a short time. Very dangerous as it is difficult to forecast and causes surprise for prevention efforts.	Wind increase ≥ 30 kt/24h or Pressure drop ≥ 30 hPa/24h	Has RI or Fast increase (≥20kt)
Max wind gain/step	Maximum wind increase between 2 consecutive reports (usually 6 hours apart). Shows the fastest local intensification rate.	`max(V_i+1 - V_i)` Unit: kt (km/h)	Positive value = storm strengthening
Max wind gain/24h	Maximum wind increase in a 24-hour window. Main criterion for determining Rapid Intensification (RI).	`max(V_t+24h - V_t)` RI if ≥ 30 kt/24h	≥ 30kt: RI ≥ 20kt: Fast
Max wind loss/step	Maximum wind weakening between 2 consecutive reports. Shows at which stage the storm weakened fastest.	`max(V_i - V_i+1)` Unit: kt (km/h)	Positive value = storm weakening
Max pressure drop/step	Maximum pressure drop between 2 consecutive reports. Pressure decrease = storm center strengthening. Reflects local deepening rate.	`max(P_i - P_i+1)` Unit: hPa	Higher value = faster strengthening
Max pressure drop/24h	Maximum pressure drop in a 24-hour window. Important index for evaluating explosive deepening / explosive intensification.	`max(P_t - P_t+24h)` Explosive if ≥ 30 hPa	≥ 30hPa: RI ≥ 20hPa: Strong
Max pressure rise/step	Maximum pressure rise between 2 consecutive reports. Pressure increase = storm weakening. Large value indicates rapid weakening (due to terrain interaction, landfall, etc.).	`max(P_i+1 - P_i)` Unit: hPa	Higher value = faster weakening
Average moving speed	Average moving speed of the storm center during the entire monitoring period by that agency.	`V_avg = S_total / T_total` Unit: kt (km/h)	Slow-moving storms (<15 km/h) usually cause prolonged heavy rain
Monitoring duration	Total time from first report to last report of that agency.	`T = t_end - t_start` Unit: hours (days)	Different agencies may monitor for different durations
TS+ Duration	Total hours with average wind ≥ 34 kt (Tropical Storm level or higher). Reflects how long the storm maintained significant intensity.	Average wind ≥ 34 kt	Longer storm = greater total damage
TY+ Duration	Total hours with average wind ≥ 64 kt (Typhoon level or higher). Storms maintaining this level longer have much greater destructive power.	Average wind ≥ 64 kt	Longer time at Typhoon level = more dangerous
Peak Intensity	Time and location (lat, lon) when the storm reached maximum wind according to each agency. Helps identify where the storm was strongest.	V_max = max(V_i)	Peak location helps assess danger for nearby areas
Latitude / Longitude	Spatial range of activity by latitude and longitude. Shows whether the storm affected area is wide or narrow.	min-max(lat), min-max(lon)	Large range = long trajectory, wide impact

Index

Meaning

Formula / Condition

Classification

ACE
Accumulated Cyclone Energy

Accumulated Cyclone Energy. Measures the total energy generated by the storm during its lifetime. Only counts reports with wind ≥ 35 kt (TS level or higher).

ACE = Σ(V_max²) / 10&sup4;
Unit: 10⁴ kt²

< 2: Low
2-6: Medium
6-15: High
≥ 15: Very High

PDI
Power Dissipation Index

Power Dissipation Index. More sensitive than ACE to extremely strong storms due to using cubic power. Reflects potential destructive power.

PDI = Σ(V_max&sup³;) / 10&sup6;
Unit: 10⁶ kt³

Higher value = greater cumulative destructive power

RI
Rapid Intensification

Rapid Intensification - storm strengthens suddenly in a short time. Very dangerous as it is difficult to forecast and causes surprise for prevention efforts.

Wind increase ≥ 30 kt/24h or Pressure drop ≥ 30 hPa/24h

Has RI or
Fast increase (≥20kt)

Max wind gain/step

Maximum wind increase between 2 consecutive reports (usually 6 hours apart). Shows the fastest local intensification rate.

max(V_i+1 - V_i)
Unit: kt (km/h)

Positive value = storm strengthening

Max wind gain/24h

Maximum wind increase in a 24-hour window. Main criterion for determining Rapid Intensification (RI).

max(V_t+24h - V_t)
RI if ≥ 30 kt/24h

≥ 30kt: RI
≥ 20kt: Fast

Max wind loss/step

Maximum wind weakening between 2 consecutive reports. Shows at which stage the storm weakened fastest.

max(V_i - V_i+1)
Unit: kt (km/h)

Positive value = storm weakening

Max pressure drop/step

Maximum pressure drop between 2 consecutive reports. Pressure decrease = storm center strengthening. Reflects local deepening rate.

max(P_i - P_i+1)
Unit: hPa

Higher value = faster strengthening

Max pressure drop/24h

Maximum pressure drop in a 24-hour window. Important index for evaluating explosive deepening / explosive intensification.

max(P_t - P_t+24h)
Explosive if ≥ 30 hPa

≥ 30hPa: RI
≥ 20hPa: Strong

Max pressure rise/step

Maximum pressure rise between 2 consecutive reports. Pressure increase = storm weakening. Large value indicates rapid weakening (due to terrain interaction, landfall, etc.).

max(P_i+1 - P_i)
Unit: hPa

Higher value = faster weakening

Average moving speed

Average moving speed of the storm center during the entire monitoring period by that agency.

V_avg = S_total / T_total
Unit: kt (km/h)

Slow-moving storms (<15 km/h) usually cause prolonged heavy rain

Monitoring duration

Total time from first report to last report of that agency.

T = t_end - t_start
Unit: hours (days)

Different agencies may monitor for different durations

TS+ Duration

Total hours with average wind ≥ 34 kt (Tropical Storm level or higher). Reflects how long the storm maintained significant intensity.

Average wind ≥ 34 kt

Longer storm = greater total damage

TY+ Duration

Total hours with average wind ≥ 64 kt (Typhoon level or higher). Storms maintaining this level longer have much greater destructive power.

Average wind ≥ 64 kt

Longer time at Typhoon level = more dangerous

Peak Intensity

Time and location (lat, lon) when the storm reached maximum wind according to each agency. Helps identify where the storm was strongest.

V_max = max(V_i)

Peak location helps assess danger for nearby areas

Latitude / Longitude

Spatial range of activity by latitude and longitude. Shows whether the storm affected area is wide or narrow.

min-max(lat), min-max(lon)

Large range = long trajectory, wide impact

RUBY (1964)

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RUBY (1964)

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Weather Agencies (8 sources)

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Advanced Meteorological Indices by Agency Automatically calculated from raw data

Advanced Indices Legend

Countries with Direct Landfall

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