The islands of Hawaii are world renowned for their generally pleasant and tranquil weather. However, the Aug. 8, 2023, wildfire tragedy on Maui was a stark reminder that Hawaii also can experience drought and hot, dry, windy weather, providing the conditions for destructive fires.
The drier parts of the state in particular have reason to be concerned about the future of fresh water available for residential, commercial and agricultural uses. In addition, changes in rainfall are expected to affect the distribution of plants in Hawaii, harming some unique native species such as silversword and increasing some invasive grass species that enhance fire danger.
Hawaii is remarkable for its exceptionally strong gradations in the average rainfall rates over very short distances. The summit of Mt. Waialeale in central Kauai, known as one of the rainiest places on Earth, receives an average of about 450 inches of rain per year. The town of Kehaka, 15 miles to the southwest and in the rain shadow, receives less than 20 inches per year on average.
Predicting Hawaii’s changing climate We created a model that zooms in on Hawaii and is able to capture those variations, including the rain shadow effect. This overall “wet gets wetter and dry gets drier” trend is generally found in global model projections of climate warming. Our computer model shows that it also applies to the rainfall gradations over the very short distances relevant for Hawaii.