The Drought Monitor even warns that, in the few isolated areas entrenched in extreme drought, “feral donkeys are moving into populated areas” and “trees are dry and dropping leaves.” That exacerbates the risk of wildfires even more, something the local National Weather Service office in Honolulu is increasingly concerned about.
“A combination of strong winds, low relative humidity and warm temperatures can contribute to extreme fire behavior,” it warned Monday, after issuing a red flag. Such warnings do not predict the igniting of wildfires, but rather indicate that any sparks could quickly turn into raging infernos.
The red flag warning in effect Monday was the first since 2012 in Hawaii in November.
Red flag warnings are more commonly issued in the late summer months of August and September when the landscape tends to become dehydrated after the dry summer season.
According to the Hawaii Wildfire Management Organization, “0.5 percent of Hawaii’s total land area burns each year, equal to or greater than the portion burned by any other U.S. state.”
Not something you see every day – Fire Weather Warnings for the west side of the Hawaiian Islands.
Relative humidity will drop below 45 percent, which, combined with wind gusts of 30-45 mph, will lead to the danger of fires spreading quickly. pic.twitter.com/ppDseMTwRW
— MyRadar Weather (@MyRadarWX) November 21, 2022
Autumn rains usually end the dry summer season, but this year they have been unreliable. In Honolulu, only 0.09 inches of rain has fallen so far in November, about an inch and a half behind the average, and only half of normal rainfall fell in October.
Since the start of the year, Honolulu has gained 9.8 inches, compared to an average of 13.6; while it represents a 28 percent deficit, it’s not nearly as bad as it was in 1998, when just 3.34 inches had fallen from mid-to-late November.
Temperatures are also at their peak in late summer, which means the greatest amount of evaporation. That dries out the landscape, with a rapid drying out between late July and early October. The drought peaked in early September this year, when 94 percent of the state was affected.
The precipitation deficit “goes back a little bit to last wet season,” explained John Bravender, a warning coordination meteorologist with the National Weather Service in Honolulu. “We had a really wet December that wiped out all the dryness, and then in January it all just turned dry.”
A series of quiet Pacific hurricane seasons balanced by a busy Atlantic limited the amount of moisture flowing northward into Hawaii during the summer.
Much of Hawaii remained dry until late October, when beneficial rains came. But the dry weather has now returned.
“In the wake of declining rainfall, Hawaii became somewhat drier amid a mostly trade wind regime,” the Drought Monitor wrote. “The result was that no further improvement was noted in Hawaii, after 9 consecutive weeks of a reduction in drought.”
The lack of rainfall this year has led to low relative humidity, sometimes below 45 percent. While 45 percent is humid by California standards, it is quite dry on a tropical island chain like Hawaii, located at about 20 degrees north latitude. In recent days, a strong clockwise high-pressure system north of the archipelago has swirled dry air to the south, while also generating gusts of wind.
Aside from the obvious wildfire risk issues, the ongoing drought is also impacting agriculture and the ecosystem. In August, about 8 percent of Maui was listed as being in “exceptional” drought — the highest level.
SFGate.com, an online news outlet based in San Francisco, reported that the lack of rain and ancient pineapple farming practices in the mountains of West Maui have made it more difficult to retain and retain water, impacting reservoir levels and farmers.
On Molokai and Maui, wild deer have encroached on farmland and have competed with livestock for resources, in part because of the arid conditions. Donkeys also roam populated areas.
“Despite continued efforts, the Ash deer population has grown to about 60,000 or more, which cannot be sustained by the Maui County environment,” reads a proclamation from Hawaii Governor David Ige (D) released on November 18. This is the governor’s fifth consecutive proclamation regarding the deer crisis, with special measures remaining in effect until Jan. 17.
“This includes corralling ash deer, culling the deer to sustainable levels, clearing vegetation along fence lines, and erecting and/or strengthening fence lines to keep ash deer away from roads, airports and runways,” the document said.
The National Weather Service’s Climate Forecast Center winter outlook does call for a gradual improvement in the state’s drought conditions.
“We’re hoping for some improvements,” says Bravender. “The wildcard is where that above-normal rainfall will occur. Especially with La Niña patterns there is more uncertainty. If it’s a stronger event, that tends to have more trade winds, which would concentrate that rainfall more over the windward parts of the islands. When it is weaker, we can see the trade winds decrease, as is typical in winter, and get more rain on the leeward side. At the moment it is the leeward sides that really need it.”
Hawaii joins large parts of the Lower 48 that are also currently experiencing significant drought. The Nov. 15 Drought Monitor update showed that 82 percent of the contiguous United States was experiencing abnormally dry or drought conditions — nearly the highest percentage on record (85 percent on Nov. 1 of this year).
A July study in the Journal of Climate noted that Hawaii’s drought, which has raged for most of the past decade, is among the most severe on record. However, it was unable to link the drought to long-term climate change because computer models evaluating its causes failed to detect human influence.
“[N]not every event has a clear and simple ‘first cause’ – natural weather mechanisms have been shown to be powerful in generating extreme events and trends over significant periods of time. wrote the Climate Program Office of the National Oceanic and Atmospheric Administration in a press release.
That of the US government fourth National Climate Reportpublished in 2018, warned that rising temperatures in the future will increase the risk of extreme drought and flooding in Pacific island communities.
Jason Samenow contributed to this report.