Tropical Storm Hone and Hurricane Gilma Set to Impact Hawaii in Rare Back-to-Back Weather Event

Tropical Storm Hone and Hurricane Gilma to Track Near Hawaii

In a rare weather event that has occurred only once in recent decades, two tropical cyclones, Tropical Storm Hone and Hurricane Gilma, are expected to track within a few hundred miles of Hawaii before the end of August.

Tropical Storm Hone to Pass Just South of Hawaii

The swirling batch of showers and thunderstorms that was aptly named Hone on Thursday is forecasted to bring gusty winds and building seas to the Hawaiian Islands this weekend as the storm approaches. However, the intensity of these winds will greatly depend on the exact direction of the storm, clarifies Alex DaSilva, a highly accomplished hurricane expert. Winds gusting between 40-60 mph are mainly expected across the southernmost islands, with stronger gusts of 60-80 mph possibly affecting far southern regions of the Big Island. An AccuWeather Local StormMax™ prediction indicates the possibility of 100 mph winds.

Though Tropical Storm Hone appeared rather disheveled on Friday, it gained momentum on Saturday and became better organized. The storm is predicted to intensify into a hurricane as it circumnavigates southwest of the islands during the new week. Winds of such high velocity pose a serious threat to power infrastructure and are capable of toppling trees. Extreme winds can escalate the risk of fires, especially on the western and southern rain-sheltered slopes of mountains and hillsides. A similar incident occurred last August with the passage of Hurricane Dora, which triggered a disastrous wildfire, marking it as Hawaii’s worst natural disaster.

Alongside gusty winds and soaring seas, heavy rainfall is also anticipated across parts of the Hawaiian Islands this weekend extending into the early part of the new week. DaSilva suggests that 1-2 inches of rain are expected across the islands, with regions like the Big Island and Maui receiving 2-4 inches. The windward side of the mountains of the Big Island may experience much higher rates, ranging from 8-16 inches with a possible AccuWeather Local StormMax™ of 20 inches. The flash flooding and mudslides that usually accompany such heavy rainfall can become significant dangers, especially on the windward, also known as the northern and eastern slopes of hills and mountains.

Hurricane Gilma to Approach Hawaii Later in the Week

Not long after the passing of Hone, Hurricane Gilma is projected to near the islands, once again raising the levels of wind, sea, and rain. The intensity of Gilma when it reaches Hawaii depends on its interaction with the cool water ahead which could weaken the hurricane. Gilma was classified as a major Category 3 hurricane midweek and though its track has been shifting, it continues to move in a generally westerly direction towards Hawaii. As it is expected to pass just north and east of the islands, locals should brace for showers, thunderstorms, and gusty winds starting late Tuesday night or Wednesday.

However, there is some reprieve as Gilma is anticipated to weaken considerably before hitting Hawaii. There is even a chance that it will diminish into a tropical depression or a wind and rainstorm by the latter half of the new week. Despite this, the combination of both Hone and Gilma will likely introduce a period of rough seas and surf to the islands, endangering boarders, swimmers, and small crafts.

Back-to-Back Tropical Cyclone Impacts Rare

While it is relatively rare, tropical storms and hurricanes do make their way near Hawaii. Historically, August bears witness to most tropical threats to the Hawaiian islands, with official records indicating 30 tropical cyclones affecting the islands since 1949. This amounts to over 40% of all tropical cyclones impacting the islands throughout the year.

Back-to-back impacts from tropical cyclones within a week’s span, however, are extremely rare. The last occurrence of this magnitude was in September 1992 when Hurricane Iniki, followed three days later by a direct hit from Tropical Depression Orlene. Similar sequences were observed in 1994 as well when two systems passed the south of the islands within eight days. It is important to remember that even without a direct strike, tropical storms and hurricanes can inflict significant danger and damage.