Hawaiʻi went from one of the driest years in a century to a series of record-breaking deluges.
In March, some areas got 3,000% more rain than normal as two Kona lows moved across the state, according to the Hawaiʻi Climate Data Portal.
University of Hawaiʻi climate data analyst Matthew Lucas said Hawaiʻi’s rainfall patterns may be starting to shift to cycles of intense dry periods and extreme rainfall events.
“Now maybe instead of getting 1% of your rainfall per day for 100 days, you get 90% of your rainfall in one day and 10% over the other 90 days,” Lucas said. While average rainfall totals may add up to the same amount, the impact on the landscape is profoundly different — imagine walking through a sprinkler versus dropping into a dunk tank.
The dousing may have cracked Hawaiʻi’s persistent drought. At the beginning of March, about 75% of the state was experiencing some level of abnormal dryness or drought. In the wake of the storms, only 45% of the state is still experiencing dry conditions, and those conditions are less severe overall.
Hawaiʻi’s winter wet season had alleviated dry conditions somewhat before the storms, but Lucas pointed to research from Australia that suggests recovery from extreme drought may only be possible through heavy rainfall events.
“At least for Australia, if you return to normal rainfall, you don't actually get out of drought. It might lessen in intensity, but it doesn't actually pull you out of drought. The only thing that pulls you out of drought is having an extreme rainfall event,” he said.
Lucas and his colleagues plan to investigate whether the same phenomenon is occurring in Hawaiʻi.
“We finally are at the point where we have the data to actually look at this trend,” he said.
Heavy rain events may resolve drought conditions, but they can also cause a new set of problems, especially for people whose livelihood relies on the land.
“If you talk to farmers in Waialua, some of them are under six feet of mud. They're not gonna be able to farm that for months,” Lucas said.
