Extreme Marshall Island Flooding: What Happened and Forecasting Future Events

Hundreds of inhabited islands dot the tropical Pacific and are vulnerable to rising waters associated with climate change. However, amid the backdrop of decadally-rising water levels, the interannual ENSO forcing, and even the lunar tidal cycle, distant large cyclones pose immediate significant and recurring threats each year in the way of very large, long-period swell resulting in infrequently-seen large surf and coastal inundation. On occasion, impacts from these events greatly exceed expectations.

In January 2024, a North Pacific cyclone brought significant inundation to many Pacific islands, even those in the South Pacific, but it was the incredible flooding in Kwajalein Atoll that made international headlines.

While reliably identifying impactful marine events is possible with the current suite of numerical weather guidance, forecasting extreme localized events is difficult due to coarse wave model resolution, limited understanding of the effect of small islands and coral atolls on passing ocean swell, and scarcity of marine observations.

This presentation will detail the January event, highlighting the far-reaching impacts and the need for improved and increased data and observations, modeling and understanding, while also bringing attention to efforts underway by several groups to help close these gaps in observations and modeling.