Hawaii Governor Declares State of Emergency as Tropical Storm Calvin Threatens Big Island with Strong Winds and Torrential Rain. Hawaii, often seen as a paradise, is now facing a dangerous situation as Tropical Storm Calvin approaches the Big Island. The governor has taken decisive action by declaring a state of emergency due to the potential threat of powerful winds and heavy rainfall.
The Central Pacific Ocean basin, where Hawaii is located, experiences an average of four to five tropical cyclones each year, with about two-thirds of these systems originating from the eastern Pacific basin and drifting westward. Historical data from NOAA’s hurricane database reveals that around 30 hurricanes have come within 200 nautical miles of the Big Island, Maui, Honolulu, or Kauai between 1950 and 2021.
The most recent significant hurricane to impact the region was Category 4 Hurricane Douglas in July 2020. Although its center passed just 30 miles north of Oahu, it caused notable damage, including downed trees and localized flooding.
Even earlier, in August 1871, a major hurricane made landfall on both the Big Island and Maui, as discovered by a study conducted in January 2018 by Eric Webb, a graduate student from the University of North Carolina – Charlotte.
While Hawaii generally experiences a lower frequency of hurricanes due to its geographical location, the risks are still present. Hawaii’s land area is relatively small, covering only about 6,400 square miles, making it the fourth-smallest state in the U.S., larger than only Connecticut, Delaware, and Rhode Island.
The central Pacific basin sees a peak in tropical cyclone activity during August, with 74 recorded between 1971 and 2013, compared to 37 in September. Additionally, July is the second most active month in the central Pacific basin, with 45 recorded cyclones.
Dr. Rick Knabb, an expert on hurricanes, emphasizes that there is no meteorological reason why a major hurricane cannot directly hit Honolulu, potentially causing severe storm surge flooding, wind damage, and rainfall flooding that could impact the nearly 400,000 metro populations (excluding tourists).
The likelihood of hurricanes approaching Hawaii depends on their direction of approach, with most tropical cyclones arriving from the east or south, and occasionally from the southwest.
In most years, the water temperature in the due east is too cool for tropical systems to develop, as cooler water currents flow from Alaska down the eastern Pacific Ocean along the U.S. West Coast and into the central Pacific. Warmer sea-surface temperatures are typically found further south in the northern Pacific, increasing the chances of a tropical cyclone reaching Hawaii when approaching from the south.
El Niño, a weather pattern occurring every three to seven years, can also influence the behavior of hurricanes. During El Niño years, warmer water extends farther north into the eastern Pacific, allowing for the formation of tropical systems closer to Hawaii. Trade winds, which usually prevent tropical cyclones from approaching the islands, relax during El Niño, making lingering storms south of Hawaii more likely to be drawn northward. However, an El Niño does not guarantee that a hurricane will impact Hawaii.
One notable example of a hurricane forming during an El Niño year is Hurricane Iniki in 1992. It originated as Tropical Depression Eighteen-E in the eastern Pacific and became a powerful hurricane after crossing into the central Pacific, causing significant damage, particularly on the island of Kauai.
While hurricanes approaching Hawaii from the east are relatively rare, several storms have weakened to tropical storms or depressions by the time they reached the islands. This is due to various factors, including drier, more stable air from the subtropical high northeast of Hawaii, stronger wind shear near the islands, and cooler sea-surface temperatures in the eastern Pacific.
However, exceptions to this pattern have occurred. Tropical Storm Iselle in 2014 became the second tropical storm to make landfall on the Big Island since 1950, causing moderate flooding. Hurricane Lane in 2018 weakened rapidly but brought heavy rainfall, resulting in extensive flooding on the Big Island. Other storms such as Hector in 2018, Lester in 2016, and Darby in 2016 also impacted Hawaii, causing varying degrees of damage.
As Tropical Storm Calvin approaches, it is expected to pass south of Hawaii County by Wednesday evening. The National Weather Service (NWS) has issued warnings about dangerous surf, damaging winds, and flash flooding associated with the storm. Rainfall of up to 10 inches is forecasted, particularly along the windward and southeast areas of the Big Island.
To prioritize public safety, Governor Josh Green has declared a state of emergency and ordered the closure of all state offices and schools on the Big Island for Wednesday. Residents are urged to take necessary precautions and prepare for the storm’s arrival.
The Hawaii Tourism Authority has issued warnings to visitors, advising them to avoid unnecessary driving, especially on the east sides of the Big Island and Maui. Hiking is discouraged due to the potential impact of strong winds and heavy rain on trails. Tourists are reminded that the storm could affect conditions across the entire state and are encouraged to prioritize safety.
While the frequency of hurricanes and tropical storms affecting Hawaii is relatively low due to its geographical size, the impact of climate change on storm frequency remains uncertain. Increased sea surface temperatures can contribute to more intense storms with extreme rainfall.
As Hawaii braces for the arrival of Tropical Storm Calvin, vigilance and preparedness are essential to minimize potential risks and ensure the safety of residents and visitors alike.
