This is storm BERTHA:BETTY that was active in 1968 in the S. Indian region with maximum winds of 93 km/h.

What was the maximum intensity of the storm?

Max Wind: 93 km/h. Min Pressure: hPa.

storm BERTHA:BETTY (1968) - Track and intensity details

Name: storm BERTHA:BETTY
Start: 1968-01-19
End: 1968-01-26
Location: S. Indian

BERTHA:BETTY (1968)

Storm Code: 1968019S12132 | Region: S. Indian
Active from 19/01/1968 to 26/01/1968 (8 days)

65 km/h

1-min Wind (JTWC)

Level 8

988 hPa

Min Pressure

3,122 km

Distance

Forecast Agencies

Agency	Max Intensity	Trajectory	Energy	highest_classification
WMO (International) (coordinates_only)	~	988	14	2,989	~	~	Undefined
BOM (Australia) (coordinates_only)	~	988	80	3,122	~	~	Undefined
DS824	93	988	79	2,998	5.08	3.94	Level 10 - Severe Storm
NEUMANN	93	988	66	2,570	16.46	13.97	Level 10 - Severe Storm
TD9636	65	~	62	2,180	0.00	0.00	Level 8 - Storm
JTWC	65	~	59	2,098	1.68	1.08	Level 8 - Storm

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)

WMO (International)
(coordinates_only)

988

2,989

Undefined

BOM (Australia)
(coordinates_only)

988

3,122

Undefined

DS824

988

2,998

5.08

3.94

Level 10 - Severe Storm

NEUMANN

988

2,570

16.46

13.97

Level 10 - Severe Storm

TD9636

2,180

0.00

Level 8 - Storm

JTWC

2,098

1.68

1.08

Level 8 - Storm

Advanced Meteorological Indices by Agency Automatically calculated from raw data

WMO (International)

Pressure Variation
Max Pressure Drop/Step	-5 hPa
Max Pressure Drop/24h	-5 hPa
Max Pressure Rise/Step (weakening)	+6 hPa
Movement & Duration
Avg Movement Speed	17.7
Tracking Time	169h (7 days)
Peak Intensity & Range
Latitude	-24.6°N – -12°N (12.6°)
Longitude	111°E – 132.3°E (21.3°)

BOM (Australia)

Pressure Variation
Max Pressure Drop/Step	-1 hPa
Max Pressure Drop/24h	-4 hPa
Max Pressure Rise/Step (weakening)	+2 hPa
Movement & Duration
Avg Movement Speed	18.5
Tracking Time	169h (7 days)
Peak Intensity & Range
Latitude	-24.6°N – -12°N (12.6°)
Longitude	111°E – 132.3°E (21.3°)

DS824

Energy
ACE (10⁴ (km/h)²)	5.08	Low
PDI (10⁶ (km/h)³)	3.94
Intensification / Weakening
Max Wind Gain/Step	+6 km/h
Max Wind Gain/24h	+9 km/h
Max Wind Loss/Step	-4 km/h
Pressure Variation
Max Pressure Drop/Step	-1 hPa
Max Pressure Drop/24h	-4 hPa
Max Pressure Rise/Step (weakening)	+1 hPa
Movement & Duration
Avg Movement Speed	17.8 km/h
Tracking Time	168h (7 days)
Time as TD+ (≥34kt)	26h (1.1d)
Peak Intensity & Range
Peak Intensity	08:00 23/01/1968 -17.2°N, 118.5°E
Latitude	-24.4°N – -12°N (12.4°)
Longitude	111.1°E – 132.3°E (21.2°)

NEUMANN

Energy
ACE (10⁴ (km/h)²)	16.46	Medium
PDI (10⁶ (km/h)³)	13.97
Intensification / Weakening
Max Wind Gain/Step	+6 km/h
Max Wind Gain/24h	+19 km/h
Max Wind Loss/Step	-6 km/h
Pressure Variation
Max Pressure Drop/Step	-1 hPa
Max Pressure Drop/24h	-5 hPa
Max Pressure Rise/Step (weakening)	+1 hPa
Movement & Duration
Avg Movement Speed	18.6 km/h
Tracking Time	138h (5.8 days)
Time as TD+ (≥34kt)	140h (5.8d)
Peak Intensity & Range
Peak Intensity	02:00 23/01/1968 -16.9°N, 119.6°E
Latitude	-24.2°N – -13.6°N (10.6°)
Longitude	111.2°E – 129.9°E (18.7°)

TD9636

Energy
ACE (10⁴ (km/h)²)	0.00
PDI (10⁶ (km/h)³)	0.00
Intensification / Weakening
Max Wind Gain/Step	+6 km/h
Max Wind Gain/24h	+28 km/h
Max Wind Loss/Step	-7 km/h
Movement & Duration
Avg Movement Speed	16.5 km/h
Tracking Time	132h (5.5 days)
Time as TD+ (≥34kt)	6h (0.3d)
Peak Intensity & Range
Peak Intensity	17:00 21/01/1968 -15°N, 125.2°E
Latitude	-22.6°N – -14.4°N (8.2°)
Longitude	111.1°E – 128.3°E (17.2°)

JTWC

Energy
ACE (10⁴ (km/h)²)	1.68	Low
PDI (10⁶ (km/h)³)	1.08
Intensification / Weakening
Max Wind Gain/Step	+6 km/h
Max Wind Gain/24h	+28 km/h
Max Wind Loss/Step	-9 km/h
Movement & Duration
Avg Movement Speed	16.7 km/h
Tracking Time	126h (5.3 days)
Time as TD+ (≥34kt)	18h (0.8d)
Peak Intensity & Range
Peak Intensity	14:00 21/01/1968 -14.9°N, 125.8°E
Latitude	-22°N – -14.5°N (7.5°)
Longitude	111.2°E – 128.2°E (17°)

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

🏳️ Australia

WMO

-12.18°, 131.33° 1968-01-19 11:16:25

BOM

-12.17°, 131.33° 1968-01-19 11:20:38

DS824 61 km/h Level 7

-12.17°, 131.33° 1968-01-19 11:20:38

NEUMANN 70 km/h Level 8

-13.99°, 129.70° 1968-01-20 09:55:56

TD9636 52 km/h Level 7

-14.61°, 128.04° 1968-01-20 13:34:35

JTWC 56 km/h Level 7

-14.63°, 128.07° 1968-01-20 13:55:09

Values are interpolated at landfall time and may differ from actual data.

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

BERTHA:BETTY (1968)

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Countries with Direct Landfall

BERTHA:BETTY

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BERTHA:BETTY (1968)

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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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