West Maui : Nāpili Region, Maui

ForecastMapRun-up ExamplesArchive

Attention: The forecast is not accurate when a tsunami, tropical storm or cyclone watch/warning is in effect. For these events, please seek information for either tsunamis or tropical storms/hurricanes. In case of a possible inundation event, please consult with local authorities and emergency responders to seek further information and direction.

One or more of the following threshold levels is/are shown in the red shaded area in the plot below:
(a) Light Impacts, (b) Hazardous Impacts, (c) Critical Impacts. To better understand their definitions, please check out the Run-up Examples.

wave run-up forecast graphic for Napili Region

The Solid Dark Blue Curve and Solid Cyan Curve display the Past and Forecast Sea Level for the previous 3 days and the next 6 days, respectively, relative to Mean Lower Low Water (MLLW, a typical NOAA datum). Past Sea Level is obtained from a combination of a local tide model with the long-period, non-tidal sea level variability being observed in real-time at Kahului Harbor. Grey vertical lines provide the associated times of high tides.

The Hatched Cyan Curve shows the forecast maximum height (or, run-up height) reached by waves along the shoreline in the Nāpili region for the next 6 days, relative to MLLW. The run-up height will always exceed or equal the tide plus background sea level described above, because the waves are riding on top of that sea level. The Hatched Dark Blue Curve shows a history of the last forecast run-up height determined for each particular time of the past 3 days; this curve provides context to show how the forecast run-up for the next 6 days differs. For more information on how the forecasts are produced, see the Details tab on the Overview Page.

If the forecast run-up extends into the red shaded region on the plot, the waves are expected to at least become a disruption for beach activities. The higher the forecast the more severe the expected effects. Click on the Run-up Examples tab for descriptions of the possible hazards.

Notifications

If you would like to receive notifications when the forecast for Nāpili (or any other West Maui region) reaches the impact stage, please register here:

The Nāpili region reaches from Hawea point north of Namalu Bay through Keonenui Bay in the south. The region is moderately developed, although it is less dense than other regions to the south. The shoreline is characterized by steep, volcanic headlands containing pocket beaches composed of sand or cobble. Some beach segments are backed by various forms of shoreline hardening. The shoreline is intermittently protected from waves by an irregular fringing reef that tends to be concentrated at headlands with sand channels fronting the sandy beaches. Buildings and infrastructure are threatened by impacts from high waves and erosion.

Run-up Thresholds

(a) Light Impact – beach activities disrupted as occasional waves may sweep the beach slopes or intermittently reach vegetation or shoreline hardening structures.

(b) Hazardous Impact – heavy wave action on beaches; likely run-up to the vegetation or shoreline hardening structures; battering of shoreline hardening structures backing some beaches; occasional overtopping of shoreline hardening; and/or possible erosion of vegetation, dunes, or bluffs in vulnerable locations.

(c) Critical Impact – strong wave battering of vegetation, dunes or bluffs; strong battering and frequent overtopping of shoreline hardening backing some beaches; likely flooding of adjacent land behind sand dunes and/or significant erosion of exposed volcanic sediment.

Run-up Examples

(a) Light Impact Event — June 14, 2018 | Nāpili Bay

Light Impact Kahana

Photo Credit: Tara Owens (Hawaiʻi and Pacific Islands King Tides Project).

Light Impact Map Napili

(a) Light Impact Event — January 9, 2019 | Nāpili Kai

Light Impact Napili

Photo Credit: Napili Kai Beach Resort.

Light Impact Map Napili

(b) Hazardous Impact Event — June 15, 2019 | Nāpili Bay

Hazardous Impact Napili

Photo Credit: Tano Taitano.

Hazardous Impact Napili

Photo Credit: Napili Kai Beach Resort.

Hazardous Impact Napili

Photo Credit: Pat Lindquist.

Hazardous Impact Map Napili

(b) Hazardous Impact Event — July 2-3, 2019 | Nāpili Bay

Hazardous Impact Napili

Photo Credit: Norm Runyan.

Hazardous Impact Napili

Photo Credit: Gene Gay.

Hazardous Impact Napili

Photo Credit: Chris Ratchford.

Hazardous Impact Napili

Photo Credit: Pat Lindquist.

Hazardous Impact Napili

Photo Credit: Pat Lindquist.

Hazardous Impact Map Napili

(b) Hazardous Impact Event — February 10, 2020 | Nāpili Bay

Hazardous Impact Napili

Photo Credit: Pat Lindquist.

Hazardous Impact Napili

Photo Credit: Pat Lindquist.

Hazardous Impact Napili

Photo Credit: Pat Lindquist.

Hazardous Impact Map Napili

(c) Critical Impact Event — 2009 | Keonenui Bay

Critical Impact Keonenui

Critical Impact Map Keonenui

(c) Critical Impact Event — October-November 2016 | Keonenui Bay

Critical Impact Keonenui

Critical Impact Keonenui

Critical Impact Map Keonenui

(c) Critical Impact Event — July 13-15, 2019 | Nāpili Bay

Critical Impact Napili

Photo Credit: Pat Lindquist.

Critical Impact Napili

Photo Credit: Pat Lindquist.

Critical Impact Napili

Photo Credit: Yvonne Fisher.

Critical Impact Napili

Photo Credit: Yvonne Fisher.

Critical Impact Napili

Photo Credit: Brenda Jarmakani.

Critical Impact Napili

Photo Credit: Don Whitebread.

Critical Impact Napili

Photo Credit: Don Whitebread and Pat Lindquist.

Critical Impact Map Napili

(c) Critical Impact Event — September 28, 2019 | Nāpili Bay

Critical Impact Napili

Photo Credit: Napili Shores Maui.

Critical Impact Napili

Photo Credit: Napili Shores Maui.

Critical Impact Map Napili

Get Involved!

We continue to collect photo documentation to fine-tune the model (if necessary) and to identify the impacts of these run-up events along the West Maui shoreline. We are specifically interested in photos around peak tides or swells, or anytime waves overtop beach features. If possible, capture the maximum extent of water running up the shoreline. The contributions from you, our citizen scientists, greatly contribute to establishing accurate thresholds for the model. Mahalo for your support!

Please submit your photos at:

To view photo submissions, please check out:

An archive of previous forecast plots can be accessed below. Select a day of interest from the calendar, or use the slider tool to quickly navigate through all available images. Two historical forecast plots are provided for each day, generated at 6:00 AM and 6:00 PM of the local time zone. To view the most recent forecast and to learn more about the different components of the graph, please go to the Forecast tab.

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