How Big were Midway's Tsunami Waves?

from NOAA: Height of the seawater at Midway's Sand Island during the March 10-11, 2011 tsunami.

               
Y axis is height of the seawater.                                       GMT = Greenwich Mean Time

MLLW = "the average of the lowest tide recorded at a tide station each day during the recording period," according to Wikipedia

WL = water level (I think!) __________________________________________________________________________

Midway Harbor dock; photo by Pete Leary

Around midnight Midway time (1 hour earlier than Hawai`i Standard Time) on March 10-11, 2011 Midway Atoll National Wildlife Refuge was hit by 4 tsunami waves that had been generated by an earthquake off Sendai, Japan.  US Fish & Wildlife's Susan White, the Pacific Reefs NWRC Project Leader, provided this preliminary data:

11:36 p.m. -- 1.5 feet
11:48 p.m. -- 4.9 feet
12:18 p.m. -- 4.3 feet
12:48 p.m. -- 2.2 feet

One or more of these waves washed completely over the smallest island of the Atoll, called Spit.  Over half of Eastern Island, where the World War II battle took place, was swamped.

All the people live on the Atoll's third island, Sand Island, 20% of which was covered by the tsunami waves.  Everyone was safe; before the first wave was predicted to hit Midway, they all  evacuated to the top floor of Charlie Barracks.  In the days after the tsunami, there does not seem to be much damage to Midway.

Midway's birds are not doing as well.  As Anna noted in her blog entry just below, the good news is that the Short-tailed Albatross chick has survived!  This is the second time it's been washed out of its nest cup!

About the Laysan Albatross, John Klavitter, the Acting Refuge Manager, says the death toll for adults and subadults is probably a "minimum of 1000," and "tens of thousands of Laysan Albatross chicks [were] lost."  Since the Black-footed Albatross generally live closer to the ocean, they may have an even higher death toll.   Pete at Midway's blog has pictures of albatross and other birds tangled in mud and bushes.  I think some of the pictures are sad.  But some other pictures show hard-working staff, volunteers and visitors rescuing birds...and even a lucky honu (green sea turtle)!

additional information: "Hawaii's Laysan and Black-footed Albatrosses have likely suffered heavy losses in last week's tsunami," by Dr. Lindsay Young