foot of rain

米テキサス州では竜巻や大雨による洪水被害が広がっており，アボット知事は２５日に非常事態を宣言しました。さてここのfoot of rainとはどのような意味でしょうか。最近，ここではお留守気味の（それはいけないことです）luaさん，どうぞ。（potter）

Floodwaters Rise in Houston; Search Goes on for 30 Missing

Floodwaters kept rising Tuesday across much of Texas as storms dumped almost another foot of rain on the Houston area, stranding hundreds of motorists and inundating the famously congested highways that serve the nation's fourth-largest city.

Meanwhile, the number of people missing in flooding along the Blanco River rose to more than 40, including a group of people who disappeared after a vacation home was swept down the river and slammed into a bridge.

Several more fatalities were reported — two in Houston, another in a vehicle on Interstate 45 and one more in Central Texas. That brought to 16 the number of people killed by the holiday weekend storms in Texas and Oklahoma.

http://abcnews.go.com/US/wireStory/12-missing-flooding-texas-sweeps-vacation-home-31302421