West Maui : Kahana, 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 Kahana

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 Kahana 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 Kahana (or any other West Maui region) reaches the impact stage, please register here:

The Kahana region reaches from Kaʻopala Beach in the north to the rocky headland at Olali St. in the south (past the “S-turns” surf break). The region is densely developed, including multi-story resorts and condominiums close to the shoreline. Between headlands, the narrow beaches are composed of sand or cobble, sometimes backed by short, vegetated dunes or volcanic sediment and rock. Some beach segments are without sand and backed by various forms of temporary or permanent shoreline hardening. The shoreline is somewhat protected from wave energy by a wide, but irregular, fringing reef interspersed with sand channels and pockets. Buildings and infrastructure are threatened by impacts from high waves and erosion.

Run-up Thresholds

(a) Light Impact – beach and nearshore activities disrupted as occasional waves may sweep the beach slopes or intermittently reach vegetation or infrastructure.

(b) Hazardous Impact – heavy wave action on beaches; battering of shoreline hardening structures; likely run-up onto low-lying, nearshore roads and into unprotected yards and houses; and/or erosion of vegetation, dunes, or volcanic sediment in vulnerable locations.

(c) Critical Impact – strong battering of shoreline hardening structures; waves frequently overtopping protective sand berms or dunes and shoreline hardening structures; flooding of adjacent land and buildings; energetic flooding over low-lying roads; and/or significant erosion of exposed volcanic sediment.

Run-up Examples

(a) Light Impact Event — July 13, 2019 | Pohaku Park

Light Impact Kahana

Photo Credit: Don McLeish.

Light Impact Map Kahana

(a) Light Impact Event — May 16, 2020 | Kaʻopala Beach

Light Impact Kahana

Photo Credit: John Seebart.

Light Impact Kahana

Photo Credit: John Seebart.

Light Impact Map Kahana

(a) Light Impact Event — July 3, 2020 | Kahana

Light Impact Kahana

Photo Credit: Don McLeish (Hawaiʻi and Pacific Islands King Tides Project) (blue star on map).

Light Impact Kahana

Photo Credit: Don McLeish (Hawaiʻi and Pacific Islands King Tides Project) (blue star on map).

Light Impact Kahana

Photo Credit: Don McLeish (Hawaiʻi and Pacific Islands King Tides Project) (orange star on map).

Light Impact Map Kahana

(b) Hazardous Impact Event — April, 2016 | Kahana Beach (Royal Kahana and Valley Isle)

Hazardous Impact Kahana

Hazardous Impact Kahana

Hazardous Impact Kahana

Hazardous Impact Map Kahana

(b) Hazardous Impact Event — May 26, 2017 | Sands of Kahana

Hazardous Impact Kahana

Photo Credit: Terry Schroeder (Hawaiʻi and Pacific Islands King Tides Project).

Hazardous Impact Map Kahana

(b) Hazardous Impact Event — October 20-22, 2018 | Kahana Coast

Hazardous Impact Kahana

October 20, 2018, 4:35pm. Photo Credit: Don McLeish.

Hazardous Impact Kahana

October 22, 2018, 4:01pm (blue star on map). Photo Credit: Don McLeish.

Hazardous Impact Kahana

October 22, 2018, 4:50pm (orange star on map). Photo Credit: Don McLeish.

Hazardous Impact Map Kahana

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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