# Hurricane Hone

Hurricane Hone was a fairly long-lived tropical cyclone that impacted the U.S. state of Hawaii in August 2024. The eighth named storm and third hurricane of the 2024 Pacific hurricane season, Hone was also the first tropical cyclone to form in the North Central Pacific tropical cyclone basin since 2019. Hone developed from two disturbances that formed over the northeastern Pacific Ocean in late August 2024. The two disturbances eventually merged into a larger area of disturbed weather on August 20. The merged system steadily became more organized, and the development of persistent deep convection over its center led to its designation as Tropical Depression One-C on August 22. The depression strengthened into a tropical storm six hours later and was named Hone. Hone gradually strengthened as it approached Hawaii from the southeast. On August 25, Hone strengthened into a hurricane while located just south of Hawaii's Big Island. After passing near the islands with maximum sustained winds of 85 mph (140 km/h), Hone began to weaken as it continued westward away from Hawaii, and the Central Pacific Hurricane Center ultimately designated Hone as a post-tropical low near the International Date Line on September 1. However, the system continued to be monitored by the Japan Meteorological Agency and Joint Typhoon Warning Center, which designated Hone a tropical and subtropical depression, respectively, in the Western Pacific, until the storm dissipated several days later.
Prior to its designation as a tropical depression, the National Hurricane Center and Central Pacific Hurricane Center warned of Hone's potential to bring heavy rainfall and dangerous rip currents to the Hawaiian Islands. The Hawaii County Civil Defense was activated ahead of the storm's anticipated passage. A tropical storm warning was issued for the Big Island, while various flood and wildfire warnings were issued for other parts of the island chain. Hone dropped very heavy rainfall across the island, with some areas seeing 18 inches (460 millimeters) or more fall during the storm's passage just 50 nautical miles south of South Point. Strong waves of up to eighteen feet in height and rip currents buffeted the coast of the island. Overall, Hone resulted in $8.05 million in property and crop damage across Hawaii, primarily on the Big Island.

## Meteorological history

On August 17, a small low-pressure area developed far to the southeast of the Hawaiian Islands. Producing disorganized showers and thunderstorms, this low-pressure area drifted near 140°W, while a second, broader area of low pressure developed to the east later that day. The western disturbance was given the designation EP90, while the eastern disturbance was designated EP91. EP90 gradually became better organized, while EP91 remained broad and disorganized, located between EP90 to its west and Tropical Storm Gilma to its east. The twin disturbances continued to interact, and eventually merged on August 21, forming a new well-defined area of low pressure. On August 22, the disturbance moved into the North Central Pacific tropical cyclone basin. By 15:00 UTC that day, the system had acquired enough deep convection over its low-level circulation center (LLCC) to be designated Tropical Depression One-C. Six hours later, the depression was upgraded to Tropical Storm Hone as the cyclone began to produce gale-force winds and its curved rainbands improved in structure.
Hone gradually strengthened through August 23 and 24. Despite lacking much deep convection, Hone had a well-defined cloud field, while over moderately warm sea surface temperatures (SSTs). Hone developed more deep convection and convective banding as it intensified. The storm moved just north of due west under the influence of a subtropical ridge to its north. Continuing on this trajectory, at 8:00 UTC on August 25, Hone strengthened into a Category 1 hurricane. Around this time, the cyclone was passing 50 nautical miles south of South Point on the Big Island. Hone reached its peak intensity at 15:00 UTC on August 25 with maximum sustained winds of 85 mph (135 km/h) and a minimum barometric pressure of 988 mbar (29.2 inHg). Increasing wind shear and drier air caused Hone to begin to weaken as it continued westward away from Hawaii. On August 26, Hone weakened back to a tropical storm. Gradually losing deep convection and organization, Hone continued to spin down over open waters while facing increasingly strong wind shear. Early on August 30, while moving steadily to the west-northwest, Hone weakened to a tropical depression. However, a persistent burst of convection within the system made it a tropical storm again early the following day. Hone continued to meander near the International Date Line. Although Hone moved northward into more favorable environmental conditions, with warm SSTs and lower wind shear, interaction with a nearby area of low pressure, dryer air and the storm's increasingly ragged low-level circulation center (LLCC) prevented Hone from strengthening more. Hone and the low eventually merged, resulting in the system's extratropical transition on September 1.
On September 2, the Japan Meteorological Agency (JMA) stated Hone had entered the Western Pacific basin as a tropical depression. However, the Joint Typhoon Warning Center (JTWC) designated Hone a subtropical depression, and noted the cyclone was in an environment marginally unfavorable for development. Hone began exhibiting a highly asymmetric convective structure, characterized by convective bands encircling a broad center, while being located under a deep subtropical trough with low to moderate vertical wind shear. The JTWC stopped tracking Hone on September 4 as it determined the system had dissipated. However, the JMA continued to monitor the cyclone, maintaining Hone as a tropical depression, until it was last noted by the agency at 06:00 UTC on September 8.

## Preparations and impact
### Preparations

Both the National Hurricane Center (NHC) and Central Pacific Hurricane Center (CPHC) warned of Hone's potential to bring heavy rainfall and strong winds and waves to portions of the main Hawaiian Islands while the system was still developing. Stronger winds from Hone presented the threat of spreading wildfires across the Big Island and Maui, a year after the devastating 2023 Hawaii wildfires which were partially influenced by Hurricane Dora. Hawaii County Civil Defense was activated on August 22, while the county's Department of Public Works assessed infrastructure on the big island ahead of Hone's expected passage to the south. The 2024 International Va’a Federation finals, an international competition in the sport of outrigger canoeing (va’a), was scheduled to end early due to the weather threats. A tropical storm watch and flood watch were both issued for the Big Island shortly after Hone's formation, while a tropical storm warning was put in place for offshore waters surrounding the entire state. The tropical storm watch was upgraded to a warning for the Big Island at 3:00 UTC on August 24. A red flag alert, indicating conditions were very favorable for a wildfire, was issued for 10AM to 6PM HST on August 24 due to Hone's strong winds pushing dry air north of the storm over parts of the island chain. Wind advisories were also issued for the islands of Maui, Oahu and Kauai. Flood mitigation equipment, such as culverts, were prepared for the coming storm by emergency management officials in Maui.
On August 24, Hawaii Governor Josh Green issued an emergency proclamation for the state. Hawaiian Airlines issued a travel waiver for those with flights to Hilo or Kona on August 24 and 25. Various high school sport and youth outdoors events were cancelled by the Hawaii High School Athletic Association and Department of Land and Natural Resources, respectively. Despite this, the Hawaii Tourism Authority informed travelers that it was still safe to come to the island during Hone's passage, but to avoid outdoor activities. All of Hawaii's campgrounds were closed through August 26 due to the storm, as well as Punaluʻu Beach and Whittington Beach parks. Hawaiʻi Volcanoes National Park was closed due to tropical storm conditions. As rounds of rain from Hone began to impact the Big Island, flash flood watches were issued there as well. While Hone moved erratically northwest of Hawaii, a tropical storm watch was issued for Kure Atoll, Midway Atoll and part of the Papahanaumokuakea Marine National Monument. The watches were eventually discontinued when Hone was designated an extratropical cyclone by the CPHC.

### Impact

Wettest tropical cyclones and their remnants in Hawaii Highest-known totals :
| Precipitation | Precipitation | Precipitation | Storm | Location | Ref. |
| Rank | mm | in | Storm | Location | Ref. |
| 1 | 1473 | 58.00 | Lane 2018 | Kahūnā Falls, Hawaii | |
| 2 | 1321 | 52.00 | Hiki 1950 | Kanalohuluhulu Ranger Station | |
| 3 | 985 | 38.76 | Paul 2000 | Kapapala Ranch 36 | |
| 4 | 700 | 28.82 | Hone 2024 | Hakalau | |
| 5 | 635 | 25.00 | Maggie 1970 | Various stations | |
| 6 | 519 | 20.42 | Nina 1957 | Wainiha | |
| 7 | 516 | 20.33 | Iwa 1982 | Intake Wainiha 1086 | |
| 8 | 476 | 18.75 | Fabio 1988 | Papaikou Mauka 140.1 | |
| 9 | 387 | 15.25 | Iselle 2014 | Kulani NWR | |
| 10 | 381 | 15.00 | One-C 1994 | Waiākea-Uka, Piihonua | |
Very heavy rainfall occurred across the Big Island of Hawaii as Hurricane Hone passed to the south, with communities in the Kaʻū District, between Nāʻālehu and South Point seeing as much as 2 in (51 mm) of rain falling per hour. Rainfall totals reached 10 in (250 mm) to 15 in (380 mm) inches across the island, with more local flooding of 18 in (460 mm) or higher. The highest rainfall occurred in Hakalau, where more than 27.5 in (700 mm) fell, while the USGS Saddle Quarry station recorded nearly 20 in (510 mm). The rainfall, however, was beneficial in some areas as it alleviated fears of wildfires and allowed red flag warnings to be discontinued. Only a small wildfire occurred on the night of August 23 in Waikoloa on the Big Island, located within the drier side of the island. Strong winds also impacted the Big Island, with a maximum wind gust of 72 mph (116 km/h) recorded at Kohala Ranch.
Life-threatening surf and rip currents impacted Hawaii as well due to Hone. The hurricane generated waves of fourteen to eighteen feet along the eastern shores of the Big Island and Maui. Flooding and fallen trees caused the closing of several roads on the Big Island, including Hawaiian Highway 11, between Kona and Hilo. At least 7,200 people lost power within the first few hours of Hone's passage. That number rose to 11,099 by midnight local time on August 25. A total of almost 26,000 people lost electricity due to Hone, the majority of them on the Big Island. However, power was restored to all but 2,000 by the next day. Strong winds and large waves lashed the island as Hone approached. The intense weather from Hone caused several flight cancellations at Hilo International Airport. A large tree fell and blocked all traffic on the Mauna Kea access road. In Maui, strong winds tore the roof off a house. A mudslide also covered part of the Hana Highway near Upper Waikani Falls. Power outages occurred on the islands of Maui and Oahu. A boat ran aground on the western shore of Kauai amidst the storm.
Hawaii County received thirty-eight damage reports, including nine major damage reports, indicating several properties were rendered uninhabitable. A total of $5 million in property damage and $10,000 in crop damage was reported. Hone resulted in $3 million in damage to several roads across the Kau and Puna districts of the Big Island. Downed power lines and utilities also caused several tens of thousands of dollars in damage across multiple Big Island districts and in Honolulu on Oahu. Overall, Hone resulted in $8.04 million in property damage in Hawaii and $10,000 in crop damage.