By Heide Brandes
OKLAHOMA CITY (Reuters) - Tropical Depression Bill pelted Oklahoma with heavy rains that swept a two-year-old toddler away in flood waters and triggered a rockslide that piled boulders on a major highway, officials said on Thursday.
Bill, the second named tropical storm of the 2015 Atlantic hurricane season, brought heavy rains into Texas and Oklahoma and is expected to dump between 2 to 4 inches of rain it travels northeast through Arkansas and Missouri into West Virginia.
Some areas could see as much as 12 inches, the National Weather Service said. It has issued a flash flood watch stretching from the Texas Coast into Illinois.
The Oklahoma Highway Patrol closed northbound lanes of Interstate 35, a major U.S. north-south corridor, about 80 miles south of Oklahoma City due to the rockslide, which injured at least one person whose vehicle was struck by a boulder.
In the southern city of Ardmore, rescue workers were looking for a 2-year-old swept away overnight.
The storm, which came ashore in Texas on Tuesday, lashed an area from Houston to Dallas with heavy rain. A 62-year-old woman was killed in central Texas when she lost control of her car on a rain-soaked highway.
Earlier severe weather in late May killed nearly 40 people in Texas and Oklahoma with storms causing flooding that damaged thousands of structures.
Tropical Depression Bill could cause rivers already swollen by those torrential rains to spill over their banks again, the National Weather Service warned.
More than 60 flights were canceled at airports in Houston and Dallas, some of the nation's busiest as of 8:30 a.m. local time, according to tracking service FlightAware.com.
(Writing and additional reporting by Jon Herskovitz; Editing by Susan Heavey)