Wave Run-Up Forecast : Kwajalein, RMI

ForecastAboutExamplesDetails

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/cyclones. In case of a possible inundation event, please consult with local authorities and emergency responders to seek further information and direction.

SLpred graphic for Kwajalein Kwajalein Color Legend

Four separate color-coded Wave Run-Up Forecasts are provided for the ocean-facing shorelines of the most populous parts of Kwajalein atoll. The Cyan, Orange, Magenta, and Green curves show the potential Inundation Height for the respective shorelines due to high tides and/or wind-generated waves. If the forecasted inundation height extends into the red shaded area, inundation is likely in low-lying areas. The forecasts are updated hourly.

The Black Curve displays the Observed and Forecast Sea Level at Kwajalein Atoll (Echo Pier) for the previous 3 days and the next 6 days, respectively, relative to Mean Lower Low Water (MLLW, a typical NOAA datum). Grey vertical lines show the associated times of the forecasted high sea level.

The PacIOOS Wave Run-Up Forecast is a tool to predict the potential occurrence of high sea levels and wave inundation impacting Kwajalein Atoll. Storm events, high waves, extreme tides, or a combination of these factors can lead to potential inundation. Due to the low elevation of the Marshall Islands, communities are vulnerable to such events.

The tool was developed to increase community resilience and enhance preparedness by providing decision-makers, agency representatives, and community members with time to plan in advance of potential flooding events. The forecast is updated hourly and dates and times are shown in local time.

The PacIOOS Wave Run-Up Forecast does not serve as a warning system. In case of a possible inundation event, please consult with local authorities and emergency responders to seek further information and direction. A similar forecast is also available for Majuro Atoll.

Contact

For more information, please contact Martin Guiles. The Wave Run-Up Forecast Tool was developed by M. Guiles, D. Luther, and M. Merrifield within the Department of Oceanography in the School of Ocean and Earth Science and Technology (SOEST) at the University of Hawaiʻi at Mānoa.

To better understand the potential extent of the forecasted inundation, a few historical events are described below for your reference. The described events correspond to the letters indicated at the right edge of the plot.

(a) 7.6 feet – December 7, 2008
Caused by weak high tide and high wind-generated wave amplitude. Some flooding occurred, as well as some damage to roads and seawalls (according to an eyewitness report).

(b) 8.7 feet – February 7, 2012
Caused by high sea level with moderate wind-generated wave amplitude. Causeway flooding occurred and school closure was reported. View the Pacific Islands Report for more details

(c) 9.4 feet – March 2, 2014
Caused by high sea level with high wind-generated waves. Flooding and displacement was reported. Please view the USGS newsletter and find additional information below.

Example Kwajalein Wave Run-up 2014
Example Kwajalein Wave Run-up 2014

During the overwash event on March 2, 2014, seawater regularly topped the manmade perimeter berm on the island of Roi-Namur, Kwajalein Atoll, and covered large areas of the adjacent land surface. The inset shows the location of the photograph. Photo credit: Peter Swarzenski, USGS.


Example Kwajalein Wave Run-up 2014

Waves overtopping the perimeter berm on the north shore of Roi-Namur, Kwajalein Atoll, during the March 2, 2014 overwash event. The inset shows the location of the photograph. Photo credit: Peter Swarzenski, USGS.

(d) 9.9 feet – December 8, 2008
Caused by moderate high tide and very high wind-generated wave amplitude. Major flooding and damage at Roi (according to an eyewitness report).

Kwajalein Shoreline Angles Used for Calculation

Kwajalein Atoll is depicted in this figure showing the four main directions used in the calculation of the wave height contribution to the forecast inundation. Seaward angles are: Cyan = 10°, Orange = 60°, Magenta = 105°, and Green = 190°.

Kwajalein Wave Run-up legend

 

Description of Kwajalein Wave Run-Up Forecast

SLpred graphic for Kwajalein

For each of the ocean-facing shorelines listed above, a color-coded Wave Run-Up Forecast was created. No forecasts are currently provided for the gray-shaded areas of the atoll. The Cyan, Orange, Magenta, and Green curves show the potential Inundation Height for the respective shorelines due to high tides, multi-day sea level variations and/or wind-generated waves. If the forecasted inundation height extends into the red shaded area, inundation is likely in low-lying areas. The forecasts are updated hourly. For the 3 days prior to the “Time Forecast Was Created,” the colored curves are showing the last valid forecast for each date/time.

The Black curve displays the Observed and Forecast Sea Level at Kwajalein Atoll at Echo Pier (inside the atoll at its southern end) for the previous 3 days and the next 6 days, respectively, relative to Mean Lower Low Water (MLLW, a typical NOAA datum). Grey vertical lines show the associated times of the forecasted high sea level. The Sea Level Forecast (also updated hourly) includes tides and multi-day sea level variations, but does not include any wind-generated wave effects.

 

Directionally-Filtered Wave Heights

Directionally-filtered wave heights graph

The Cyan, Orange, Magenta, and Green curves in this plot show the forecasted significant wave heights for each of the respective shorelines 6 days into the future (to the right of the “Time Forecast Was Created”). The forecasts are based on directionally filtered wave spectra provided by the NOAA Wave Watch III model, using locations near Kwajalein Atoll. For the 3 days prior to the “Time Forecast Was Created,” the dashed curves are showing the last valid forecast for each date/time. If available, significant wave heights based on directionally filtered observations are also shown, plotted as colored circles.