mudflat

　オーストラリアにある島で、砂浜に"help"と書いてあるところに孤立したカップルがいるのが発見されました。
Marooned couple write 'Help' in the sand

A couple was rescued today from a remote beach where they'd spelled out the word "Help" in the sand.

The pair became stranded on an island off the northeast coast of Australia Tuesday morning “after their boat smashed into rocks in a freak storm,” according to a statement from the Central Queensland Helicopter Rescue Service.

The couple spent eight hours marooned on the island, aptly named Avoid Island, enduring three storms and taking shelter in mudflats, the statement said.

They were airlifted to safety after activating an EPIRB, a device that transmits coded messages via satellite.

http://abcnews.go.com/International/marooned-couple-write-sand/story?id=53249196

　取り上げる単語は"mudflat"です。『ジーニアス英和辞典』第４版（大修館）で調べてみると、「干潟」という意味がありました。「泥」という意味の"mud"と「湿地、沼地、浅瀬」などという意味の"flat"が合わさってできた語です。LDOCEでは、 "an area of muddy land that is covered by the sea when it comes up at high tide and uncovered when it goes down at low tide"と定義されています。(Akim)