1865 Ardonia arrocane season
| 1865 Ardonia arrocane season | |
 | |
| Seasonal boundaries | |
|---|---|
| First system formed | May 24, 1865 |
| Last system dissipated | August 6, 1865 |
| Strongest storm | |
| Name | "Port Kazu" |
| • Maximum winds | 165 mph (270 km/h) (1-minute sustained) |
| • Lowest pressure | 911 mbar (hPa; 26.90 inHg) |
| Seasonal statistics | |
| Total depressions | 13 |
| Total storms | 13 |
| Arrocanes | 5 |
| Major arrocanes (Cat. 3+) |
3 |
| ACE | 93.585 |
| Total fatalities | 242 total |
| Total damage | $17.7 billion (1865 USD) |
| Related articles | |
Ardonia arrocane seasons 1864, 1865, 2019 | |
The 1865 Ardonia arrocane season was the earliest season for which a complete record of tropical cyclone activity in Ardonia is presently documented. The season was highly active, producing 13 tropical depressions, all of which became tropical storms, five of which strengthened into arrocanes, and three of which became major arrocanes. One system attained Category 5 intensity. The season's first tropical cyclone formed on May 24, while the final system ceased to be a tropical cyclone on August 6. Collectively, the season produced an accumulated cyclone energy (ACE) value of 93.585.
Tropical cyclone activity was particularly concentrated during July, when most of the season's strongest systems developed. The most intense cyclone of the season was Tropical Cyclone Nine, commonly known as the Port Kazu arrocane, which attained Category 5 intensity with maximum sustained winds of 165 mph (270 km/h) and a minimum central pressure of 911 mbar (26.90 inHg). Nine was the earliest documented Category 5 arrocane in the historical record and produced an ACE value of 44.28, accounting for nearly half of the season's total ACE. Two other systems, Seven and Six, also attained major arrocane intensity.
The season was exceptionally destructive and deadly. Tropical cyclones collectively caused 242 fatalities and approximately $17.7 billion in damage in 1865 USD. Nine was responsible for the largest share of both, causing 138 deaths and approximately $10.2 billion in damage after affecting portions of southern Ardonia, including Cydonia and K'arthen. Several other systems affected locations throughout Ardonia during the season.
The season occurred during a substantial transition in the El Niño–Southern Oscillation (ENSO). Moderate El Niño conditions were present at the beginning of 1865 before steadily weakening during the spring. Conditions became near-neutral by the beginning of the arrocane season and transitioned from warm-neutral to cold-neutral during the height of activity in July. La Niña conditions subsequently developed later in the year. The annual ENSO anomaly averaged −0.02 °C, corresponding to cold-neutral conditions.
Seasonal forecasts
| Source | Date | Named storms |
Arrocanes | Major arrocanes |
| Seasonal forecasts | None issued | |||
| Actual activity | 13 | 5 | 3 | |
No seasonal forecasts of tropical cyclone activity are known to have been issued for the 1865 Ardonia arrocane season. The season represents the earliest complete tropical cyclone season in the documented Ardonia record, and consequently no preceding season or established historical climatology was available for comparison. Modern seasonal forecasting practices had also not yet been established.
The Ardonia Meteorological Organization (AMO) and National Arrocane Center (NAC), which would later become involved in the coordination and operational monitoring of tropical cyclone activity in Ardonia, were not established until 1952. As a result, the activity of the 1865 season was documented without the seasonal outlooks that would characterize later periods of the tropical cyclone record.
The season ultimately produced 13 tropical storms, five arrocanes, and three major arrocanes. These totals subsequently became the earliest documented benchmark for tropical cyclone activity in Ardonia and would later serve as the primary historical comparison for seasonal activity until additional seasons were incorporated into the record.
Seasonal summary
Early activity
The 1865 Ardonia arrocane season began on May 24 with the formation of Tropical Storm One, marking the beginning of the earliest complete tropical cyclone season in the documented Ardonia record. One remained a tropical storm throughout its brief existence before transitioning out of the tropical phase on May 26. Activity then ceased for more than two weeks before Tropical Storm Two developed in June. The cyclone remained below arrocane intensity and ceased to be a tropical cyclone on June 13, after which another extended period without tropical activity followed.
Activity began to increase toward the end of June with the formation of Tropical Storm Three. The system persisted into July before degenerating into a remnant low on July 1. This marked the beginning of a significant change in the character of the season, as tropical cyclogenesis became considerably more frequent during July. Arrocane Four subsequently became the first arrocane of the season, reaching Category 1 intensity, while Tropical Storm Five developed shortly thereafter.
The early portion of the season was therefore characterized primarily by relatively weak and separated tropical cyclones. None of the first five systems became a major arrocane, contrasting sharply with the substantially stronger activity that followed during the middle and latter portions of July.
Peak activity
The season entered its most active period during mid-July. Arrocane Six strengthened rapidly and became the first major arrocane of the season, ultimately attaining Category 3 intensity with maximum sustained winds of 125 mph (205 km/h) and a minimum central pressure of 951 mbar (28.08 inHg). Six transitioned into an extratropical cyclone on July 16, but its development marked the beginning of a prolonged period in which several tropical cyclones developed in relatively rapid succession.
Arrocane Seven subsequently became substantially more intense, reaching Category 4 intensity with maximum sustained winds of 145 mph (235 km/h) and a minimum central pressure of 929 mbar (27.43 inHg). Commonly known as the Trinity Islands arrocane, Seven became the second major arrocane of the season. Arrocane Eight also developed during this period and attained Category 2 intensity. By the latter half of July, multiple tropical cyclones were simultaneously active across the Ardonia Ocean, representing the greatest concentration of activity during the season.
The most intense cyclone of the season was Arrocane Nine, commonly known as the Port Kazu arrocane. The system developed on July 18 and intensified considerably during its lifespan, eventually becoming the season's only Category 5 arrocane. Nine first attained Category 5 intensity on July 26 and reached its peak later that day, with maximum sustained winds of 165 mph (270 km/h) and a minimum central pressure of 911 mbar (26.90 inHg). At the time, these values made Nine the most intense tropical cyclone in the documented Ardonia record. The cyclone remained at Category 5 intensity into July 27 before weakening and ultimately transitioning into an extratropical cyclone on July 29.
Nine generated an accumulated cyclone energy (ACE) value of 44.28, accounting for approximately 47% of the season's total ACE of 93.585. Combined with the substantial contributions from Seven and Six, the succession of major arrocanes during July was responsible for much of the season's overall tropical cyclone activity.
End of the season
Additional tropical cyclones developed while the season's strongest systems were active. Tropical Storm Ten formed during the latter half of July but remained below arrocane intensity before becoming extratropical on July 23. Tropical Storm Eleven followed and persisted through July 28 before transitioning into an extratropical cyclone on July 29. Tropical Storm Twelve developed near the end of July and continued into August, becoming the penultimate tropical cyclone of the season and transitioning into an extratropical cyclone on August 3.
Tropical Storm Thirteen was the final system of the season. It developed during early August and remained relatively weak, eventually weakening to a tropical depression on August 6. The system degenerated into a remnant low later that day, marking the end of tropical cyclone activity for the 1865 season. Although the remnants of Thirteen persisted for several additional days, no further tropical cyclones developed.
Overall, the 1865 season produced 13 tropical storms, five arrocanes, and three major arrocanes, including one Category 5 arrocane. The season generated 93.585 units of ACE, with activity heavily concentrated during July. Tropical cyclone activity also coincided with an ongoing transition in the El Niño–Southern Oscillation (ENSO). El Niño conditions present earlier in 1865 had weakened substantially by the beginning of the season, with conditions progressing through warm-neutral and into cold-neutral during July. La Niña conditions subsequently developed later in the year.
Systems
Tropical Storm One
| Tropical storm (AAWS) | |
|---|---|
  | |
| Duration | May 24 – May 26 |
| Peak intensity | 45 mph (75 km/h) (1-min); 994 mbar (hPa) |
Tropical Storm One formed at 12:00 UTC on May 24, becoming the first tropical cyclone of the 1865 season and the earliest system in the complete Ardonia tropical cyclone record. The cyclone attained maximum sustained winds of 45 mph (75 km/h) and a minimum central pressure of 994 mbar (29.35 inHg). It remained at tropical storm intensity before ceasing to be a tropical cyclone at 12:00 UTC on May 26. Over its two-day tropical lifespan, One generated 0.65 units of accumulated cyclone energy (ACE).
One affected Cydonia, particularly Meridian. Damage in Meridian totaled $520 million in 1865 USD, and two fatalities were attributed to the cyclone.
Tropical Storm Two
| Tropical storm (AAWS) | |
|---|---|
 | |
| Duration | June 12 – June 13 |
| Peak intensity | 40 mph (65 km/h) (1-min); 997 mbar (hPa) |
Tropical Storm Two formed at 18:00 UTC on June 12, following more than two weeks without tropical cyclone activity. The system briefly attained tropical storm intensity, reaching maximum sustained winds of 40 mph (65 km/h) and a minimum pressure of 997 mbar (29.44 inHg). Two ceased to be a tropical cyclone at 12:00 UTC on June 13 after a tropical duration of 18 hours and generated 0.245 units of ACE.
The storm affected Nandosa Ridge, causing $2.5 million in damage. No fatalities were recorded.
Tropical Storm Three
| Tropical storm (AAWS) | |
|---|---|
 | |
| Duration | June 28 – July 1 |
| Peak intensity | 60 mph (95 km/h) (1-min); 986 mbar (hPa) |
Tropical Storm Three formed at 06:00 UTC on June 28 and became the first cyclone of the season to persist into July. The storm attained maximum sustained winds of 60 mph (95 km/h) and a minimum pressure of 986 mbar (29.12 inHg). It remained below arrocane intensity throughout its lifetime before ceasing to be a tropical cyclone at 18:00 UTC on July 1. Three generated 2.36 units of ACE.
Three affected Mt. Tempus, an island near Mt. Tempus, and the Basalt Mines in Felden. The island sustained $1.25 million in damage, Mt. Tempus sustained $10.5 million, and the Basalt Mines sustained $50.25 million. Three caused $62 million in damage overall and 22 fatalities, including three at Mt. Tempus and 19 at the Basalt Mines.
Arrocane Four
| Category 1 arrocane (AAWS) | |
|---|---|
 | |
| Duration | July 9 – July 11 |
| Peak intensity | 80 mph (130 km/h) (1-min); 986 mbar (hPa) |
Arrocane Four formed at 12:00 UTC on July 9 and became the first arrocane of the season. The cyclone reached Category 1 intensity on the Ardonia arrocane wind scale, attaining maximum sustained winds of 80 mph (130 km/h) and a minimum pressure of 986 mbar (29.12 inHg). Four ceased to be a tropical cyclone at 12:00 UTC on July 11 after two days as a tropical cyclone and generated 2.68 units of ACE.
The arrocane affected the Pearl Islands, where it caused $15.5 million in damage and three fatalities.
Tropical Storm Five
| Tropical storm (AAWS) | |
|---|---|
 | |
| Duration | July 12 – July 13 |
| Peak intensity | 50 mph (85 km/h) (1-min); 990 mbar (hPa) |
Tropical Storm Five formed at 12:00 UTC on July 12. The cyclone reached maximum sustained winds of 50 mph (85 km/h) and a minimum pressure of 990 mbar (29.23 inHg), remaining below arrocane intensity. It ceased to be a tropical cyclone at 18:00 UTC on July 13 after 30 hours and generated 0.7675 units of ACE.
Five affected Blade Island, causing approximately $10,000 in damage. No fatalities were recorded.
Arrocane Six
| Category 3 arrocane (AAWS) | |
|---|---|
 | |
| Duration | July 14 – July 16 |
| Peak intensity | 125 mph (205 km/h) (1-min); 951 mbar (hPa) |
Arrocane Six formed at 00:00 UTC on July 14 and became the first major arrocane of the season. During the 24-hour period beginning at 00:00 UTC on July 14, its maximum sustained winds increased from 40 mph (65 km/h) to 105 mph (165 km/h), an increase of 65 mph (100 km/h). Six ultimately reached Category 3 intensity, peaking at 125 mph (205 km/h) with a minimum central pressure of 951 mbar (28.08 inHg). It ceased to be a tropical cyclone at 18:00 UTC on July 16 and generated 10.035 units of ACE.
Six affected K'arthen and locations in the Wilderness. Markar sustained $215 million in damage and three fatalities. Bhengorn sustained $555 million in damage and nine fatalities, while Fort Hacksaw sustained $265 million and seven fatalities. Overall, Six caused $1.035 billion in damage and 19 deaths.
The 65 mph (100 km/h) increase in Six's maximum sustained winds over 24 hours ranks sixth among the greatest 24-hour wind increases in the currently compiled Ardonia tropical cyclone record.
Arrocane Seven
| Category 4 arrocane (AAWS) | |
|---|---|
 | |
| Duration | July 16 – July 23 |
| Peak intensity | 145 mph (230 km/h) (1-min); 929 mbar (hPa) |
Arrocane Seven, commonly known as the Trinity Islands arrocane, formed at 18:00 UTC on July 16. It intensified into the second major arrocane of the season and ultimately reached Category 4 intensity, with maximum sustained winds of 145 mph (235 km/h) and a minimum central pressure of 929 mbar (27.43 inHg). Seven remained a tropical cyclone for exactly seven days before becoming extratropical at 18:00 UTC on July 23. The cyclone generated 22.5925 units of ACE, the second-highest total of the season.
Seven severely affected Cydonia. Meridian sustained $2.85 billion in damage and 21 fatalities. Across the Trinity Islands, the southern islands sustained $795 million in damage and eight deaths, the central islands sustained $1.65 billion and 13 deaths, and the northern islands sustained $400 million and nine deaths. Nandosa Ridge sustained a further $175 million in damage and six fatalities. In total, Seven caused $5.87 billion in damage and 57 deaths.
Within the currently compiled Ardonia record, Seven's 145 mph (235 km/h) peak winds are tied for ninth-highest, while its minimum pressure of 929 mbar ranks eighth-lowest. Its ACE of 22.5925 ranks sixth among individual tropical cyclones, its 57 fatalities rank tenth among the deadliest cyclones, and its seven-day tropical duration is tied for fifth-longest.
Arrocane Eight
| Category 2 arrocane (AAWS) | |
|---|---|
 | |
| Duration | July 17 – July 21 |
| Peak intensity | 105 mph (165 km/h) (1-min); 974 mbar (hPa) |
Arrocane Eight formed at 18:00 UTC on July 17 during the increasingly active period of mid-July. The cyclone strengthened to Category 2 intensity, reaching maximum sustained winds of 105 mph (165 km/h) and a minimum pressure of 974 mbar (28.76 inHg). Eight ceased to be a tropical cyclone at 12:00 UTC on July 21 after a tropical duration of three days and 18 hours. It generated 6.16 units of ACE.
Eight affected rural areas and caused approximately $50,000 in damage. No fatalities were recorded.
Arrocane Nine
| Category 5 arrocane (AAWS) | |
|---|---|
 | |
| Duration | July 17 – July 29 |
| Peak intensity | 165 mph (270 km/h) (1-min); 911 mbar (hPa) |
Arrocane Nine, commonly known as the Port Kazu arrocane, formed at 18:00 UTC on July 17 and became the longest-lived, most intense, costliest, and deadliest cyclone of the season. The cyclone eventually attained Category 5 intensity on July 26. At 18:00 UTC that day, Nine reached its peak intensity with maximum sustained winds of 165 mph (270 km/h) and a minimum central pressure of 911 mbar (26.90 inHg). The system remained at Category 5 intensity into July 27 before weakening, and became extratropical at 00:00 UTC on July 29.
Nine remained a tropical cyclone for 11 days and 6 hours, the longest tropical duration in the currently compiled Ardonia record. It generated 44.28 units of ACE, accounting for approximately 47.3% of the season's total and representing the highest individual-storm ACE value in the current record. Nine's 165 mph (270 km/h) maximum winds rank fifth among the strongest arrocanes currently documented, while its minimum pressure of 911 mbar likewise ranks fifth among the most intense by central pressure. Nine was also the earliest documented Category 5 arrocane in the complete seasonal record.
Nine affected the Pearl Islands, Cydonia, and K'arthen. The Pearl Islands sustained $4.5 million in damage and four fatalities. In Cydonia, Port Kazu sustained $6.64 billion in damage and 37 fatalities, while Kaeru sustained $2.3 billion and 17 fatalities. The Aridia Cliffs recorded $800 million in damage and 48 deaths, the greatest fatality total at any single affected location. The Cydonia Mines sustained $450 million and 23 fatalities, while Phaethon sustained $16.7 million and five fatalities. In K'arthen, Mt. Kaelos sustained $1.5 million in damage and four fatalities. Overall, Nine caused $10.2127 billion in damage and 138 deaths, accounting for approximately 57% of all fatalities and nearly 58% of all damage during the season.
Tropical Storm Ten
| Tropical storm (AAWS) | |
|---|---|
 | |
| Duration | July 20 – July 23 |
| Peak intensity | 70 mph (110 km/h) (1-min); 985 mbar (hPa) |
Tropical Storm Ten formed at 06:00 UTC on July 20 while several other tropical cyclones were simultaneously active. The storm strengthened to just below arrocane intensity, attaining maximum sustained winds of 70 mph (110 km/h) and a minimum pressure of 985 mbar (29.09 inHg). Ten ceased to be a tropical cyclone at 00:00 UTC on July 23 after two days and 18 hours and generated 2.435 units of ACE. No damage or fatalities were recorded.
Tropical Storm Eleven
| Tropical storm (AAWS) | |
|---|---|
 | |
| Duration | July 27 – July 29 |
| Peak intensity | 50 mph (85 km/h) (1-min); 988 mbar (hPa) |
Tropical Storm Eleven formed at 12:00 UTC on July 27 as Nine was beginning to weaken from Category 5 intensity. Eleven attained maximum sustained winds of 50 mph (85 km/h) and a minimum pressure of 988 mbar (29.18 inHg). The cyclone became extratropical at 00:00 UTC on July 29 after 36 hours as a tropical cyclone and generated 0.7675 units of ACE.
Eleven affected the Shrouded Islands, causing approximately $250,000 in damage and one fatality.
Tropical Storm Twelve
| Tropical storm (AAWS) | |
|---|---|
 | |
| Duration | August 2 – August 3 |
| Peak intensity | 40 mph (65 km/h) (1-min); 997 mbar (hPa) |
Tropical Storm Twelve formed at 00:00 UTC on August 2, becoming the first tropical cyclone of the month. The storm reached maximum sustained winds of 40 mph (65 km/h) and a minimum pressure of 997 mbar (29.44 inHg). Twelve became extratropical at 00:00 UTC on August 3 after exactly one day as a tropical cyclone and generated 0.3675 units of ACE. No damage or fatalities were recorded.
Tropical Storm Thirteen
| Tropical storm (AAWS) | |
|---|---|
 | |
| Duration | August 6 – August 6 |
| Peak intensity | 40 mph (65 km/h) (1-min); 997 mbar (hPa) |
Tropical Storm Thirteen was the final tropical cyclone of the season, forming at 00:00 UTC on August 6. The system briefly attained tropical storm intensity, with maximum sustained winds of 40 mph (65 km/h) and a minimum pressure of 997 mbar (29.44 inHg). It weakened to a tropical depression by 12:00 UTC and became a remnant low at 18:00 UTC, marking the end of tropical cyclone activity for the season. The remnant circulation persisted for several additional days. Thirteen generated 0.245 units of ACE. No damage or fatalities were recorded.
Season effects
This is a table of all tropical cyclones that formed during the 1865 Ardonia arrocane season. It includes their designation, duration, peak classification and intensity, areas affected, damage, and death totals. Damage and deaths include totals while a system was extratropical, a wave, or a low where applicable, and all damage figures are in 1865 USD.
| Ardonia arrocane wind scale | ||||||
| TD | TS | C1 | C2 | C3 | C4 | C5 |
| Storm name |
Dates active | Storm category at peak intensity |
Max 1-min wind mph (km/h) |
Min. press. (mbar) |
Areas affected | Damage (USD) |
Deaths | |||
|---|---|---|---|---|---|---|---|---|---|---|
| One | May 24–26 | Tropical storm
|
45 (75)
|
994
|
Cydonia (Meridian) | $520 million | 2 | |||
| Two | June 12–13 | Tropical storm
|
40 (65)
|
997
|
Nandosa Ridge | $2.5 million | None | |||
| Three | June 28 – July 1 | Tropical storm
|
60 (95)
|
986
|
Mt. Tempus (island), Mt. Tempus, Felden (Basalt Mines) | $62 million | 22 | |||
| Four | July 9–11 | Category 1 arrocane
|
80 (130)
|
986
|
Pearl Islands | $15.5 million | 3 | |||
| Five | July 12–13 | Tropical storm
|
50 (85)
|
990
|
Blade Island | $10,000 | None | |||
| Six | July 14–16 | Category 3 arrocane
|
125 (205)
|
951
|
K'arthen (Markar), Bhengorn, Fort Hacksaw | $1.035 billion | 19 | |||
| Seven | July 16–23 | Category 4 arrocane
|
145 (235)
|
929
|
Cydonia (Meridian, Trinity Islands), Nandosa Ridge | $5.87 billion | 57 | |||
| Eight | July 17–21 | Category 2 arrocane
|
105 (165)
|
974
|
Rural areas | $50,000 | None | |||
| Nine | July 17–29 | Category 5 arrocane
|
165 (270)
|
911
|
Pearl Islands, Cydonia (Port Kazu, Kaeru, Aridia Cliffs, Cydonia Mines, Phaethon), K'arthen (Mt. Kaelos) | $10.2127 billion | 138 | |||
| Ten | July 20–23 | Tropical storm
|
70 (110)
|
985
|
None | None | None | |||
| Eleven | July 27–29 | Tropical storm
|
50 (85)
|
988
|
Shrouded Islands | $250,000 | 1 | |||
| Twelve | August 2–3 | Tropical storm
|
40 (65)
|
997
|
None | None | None | |||
| Thirteen | August 6 | Tropical storm
|
40 (65)
|
997
|
None | None | None | |||
| Season aggregates | ||||||||||
| 13 systems | May 24 – August 6 | 165 (270) | 911 | $17.71801 billion | 242 | |||||