Hawaii Faces a Rare Dual Hurricane Threat Through This Weekend

For the third year in the row, Hawaii is being threatened by hurricanes. Despite being a minuscule target in the middle of the Pacific, two storms are taking aim at the state.

Hurricane Madeline is the first in line with Lester hot on its heels. Hurricane watches are up for the Big Island, and if one of the storms makes landfall, it would be the first time on record that the Big Island has taken a direct hit from a hurricane.

Historically, it’s fairly rare for hurricanes to threaten the Aloha State, let alone make landfall. The past three years have been very active in comparison, and research points to more hurricane activity in the region as the world warms. The last hurricane to hit Hawaii was Hurricane Iniki, which made landfall in Kauai in 1992.

Both storms are major hurricanes, ranked Category 3 or stronger. Hurricane Madeline is the closer of the two hurricanes to Hawaii, churning about 436 miles east of the Big Island. It’s packing winds of around 120 mph, making it a Category 3 hurricane. To get a better sense of what’s going on with Madeline, hurricane hunter aircraft are scheduled to make a pass through the storm later Tuesday.

Hurricane Madeline churning in the Pacific, with the Big Island of Hawaii just visible to the west.

Credit: NOAA Satellites

Hurricane Lester is further away but the stronger of the two. Its winds are gusting up to 138 mph, or Category 4 intensity. That also makes Lester the strongest hurricane to form in the eastern Pacific this year.

Hurricane force winds could impact the Big Island within the next 48 hours. Madeline is forecast to track just off the southern tip of the Big Island by late Wednesday or early Thursday morning, local time. A direct hit isn’t out of the question, and a hurricane watch is in place for the entire island as is a tropical storm warning. Tropical storm watches are in place for the islands of Maui, Lanai and Molokai as well.

In addition to wind, the Big Island could be drenched with heavy rain. According to re-insurer Aon Benfield, up to 15 inches of rain are possible for the Big Island. That could cause flash flood and dangerous mudslides, especially on hilly slopes.

The forecast track and cone of probability for Hurricane Madeline through Sunday.

Credit: National Hurricane Center

Lester’s potential impacts are quite a bit more uncertain. The storm could approach the Big Island on Saturday morning and impact some of the other Hawaiian islands throughout the weekend, transitioning from a hurricane to a tropical storm over that time.

There’s also a good chance it could pass north of the islands with some rain and heavy surf the only impacts Hawaii would see.

The forecast track and cone of probability for Hurricane Lester through Sunday.

Credit: National Hurricane Center

There’s even a scenario where having two storms in such close proximity could steer them both away from the island chain altogether. Bob Henson at Wunderground first drew attention to the possibility of the Fujiwhara Effect coming into play. When two hurricanes come within 800 miles of each other, they start to rotate around a central point like dancers, eventually changing their tracks.

“In a case like this, the eastern storm (Lester) would angle northward and the western storm (Madeline) would angle southward. Both effects would tend to angle Madeline and Lester away from Hawaii,” Henson wrote.

Forget El Niño, the Pacific Meridional Mode could be responsible for the recent uptick in Pacific hurricane activity. El Niño is so last year. The climate phenomenon, characterized by warmer than normal waters in the eastern tropical Pacific, tends to help boost hurricane activity in the eastern Pacific basin.

“It’s about three times more likely for Hawaii to be impacted by a tropical cyclone in an El Niño vs. a La Niña year,” Phil Klotzbach, a hurricane forecaster at Colorado State University, told Climate Central last year.

In 2015, there were a record 15 named storms that made it to the central Pacific. None hit Hawaii but a few got pretty close.

The absence of El Niño doesn’t mean there aren’t other natural factors that could be behind the dynamic duo. Enter the Pacific Meridional Mode (PMM), a fairly obscure climate pattern of warmer than normal waters in the subtropical Pacific (for geography buffs, subtropical generally means waters north of 10°N).

“El Niño is only one factor that may induce tropical cyclones near Hawaii,” Hiroyuki Murakami, a hurricane researcher at the Geophysical Fluid Research Laboratory, said. “The PMM is a new index which (scientists have) recently paid much more attention.”

The warm water could help sustain storms in the normally chilly (for the subtropics) water around Hawaii.

Climate change is also a likely player helping fuel the storms. While there hasn’t been any specific attribution work done on these storms, this year is definitely in line with what scientists expect to see in the Hawaii region as the world continues to warm.

“We speculate that this year is a combo of PMM in its positive phase and also anthropogenic forcing related to global warming,” Murakami said.

Global warming is, well, global, and the subtropics where Hawaii is located are no exception. Sea surface temperatures in the region are currently running 2°-4°F above normal for this time of year.

Murakami and his colleagues have done attribution work on Hawaii’s recent dramatic hurricane seasons, which have seen a spate of storms spring up but for the most part, just miss the islands.

The 2014 season was particularly active and Murakami’s research has attributed 90 percent of the risk to climate change. The caveat for this line of research is there’s less data on central Pacific hurricanes than, say, the Atlantic basin so there’s still uncertainty in future projections.

That said, Murakami said most models are in agreement that the number of storms are likely to increase in the next decade or two.

“We may see more similar years like this year in the near future,” he said.