Amy Gilmour, a volunteer from San Antonio, Texas, walks past a pile of debris, which included parts of destroyed homes, that amassed when the Blanco River flooded during the Memorial Day weekend rains in Wimberley, Texas May 26, 2015. Torrential rains have killed at least 10 people in Texas and Oklahoma, including three in Houston where floods turned streets into rivers and led to about 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

A totaled Porsche rests against the foundation of a home destroyed by the Memorial Day weekend floods in Wimberley, Texas May 26, 2015. Torrential rains have killed at least 10 people in Texas and Oklahoma, including three in Houston where floods turned streets into rivers and led to about 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

Amy Gilmour, a volunteer from San Antonio, Texas, helps pick up debris from the backyards of flood damaged homes along the Blanco River in Wimberley, Texas May 26, 2015. Torrential rains have killed at least 10 people in Texas and Oklahoma, including three in Houston where floods turned streets into rivers and led to about 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

Motorists survey the flood waters in southwest Houston, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Daniel Kramer 

Volunteers gather in a shopping center parking lot before dispersing to help with flood relief efforts in San Marcos, Texas May 26, 2015. Torrential rains have killed at least 10 people in Texas and Oklahoma, including three in Houston where floods turned streets into rivers and led to about 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

A man wades through floodwaters in southwest Houston, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Daniel Kramer 

Dustin Nichols helps clean up his parents' flood damaged home in San Marcos, Texas May 26, 2015. Torrential rains have killed at least 10 people in Texas and Oklahoma, including three in Houston where floods turned streets into rivers and led to about 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

Cars and houses are seen covered by floodwaters in southwest Houston, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Daniel Kramer 

Flood damaged cars and debris are piled up against a line of trees in San Marcos, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

Sonia Porter (L) reacts to Devin Sadler, 9, picking up a waterlogged gun during clean-up efforts at John and Ruth Hansen's flood damaged home in San Marcos, Texas May 26, 2015. Torrential rains have killed at least 10 people in Texas and Oklahoma, including three in Houston where floods turned streets into rivers and led to about 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa TPX IMAGES OF THE DAY

Flood damaged vehicles and debris are strewn across lawns throughout the length of Bogie Drive in San Marcos, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

Flood waters cover several cars on the South I-610 frontage road in Houston, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Daniel Kramer 

Gilbert Hernandez cleans debris out of his flood damaged home in San Marcos, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

A mobile home and debris sit in a front yard full of standing water in San Marcos, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

Larry Bowls surveys the flood damage to his friend's neighborhood in San Marcos, Texas May 26, 2015. Torrential rains have killed at least 10 people in Texas and Oklahoma, including three in Houston where floods turned streets into rivers and led to about 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

Members of a family abandon their car as floodwaters cover the exit ramp in southwest Houston, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Daniel Kramer 

Vehicles are stranded by flood waters in south Houston, Texas May 26, 2015. Rescue workers searched on Tuesday for 12 people missing in Texas after torrential rains slammed the state and Oklahoma during the Memorial Day weekend, killing seven people and causing floods that destroyed homes and swept away bridges. REUTERS/Daniel Kramer 

Sarah Alvarez and her mother Janie De Los Santos (R), take a break from cleaning their flood damaged house in San Marcos, Texas May 26, 2015. Torrential rains have killed at least 10 people in Texas and Oklahoma, including three in Houston where floods turned streets into rivers and led to about 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

A woman walks in the flood waters in southwest Houston, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Daniel Kramer 

Don Simons (L) and Clint Followel, volunteers from the First Baptist Church in San Marcos, Texas, help clean Toby McLroy's flood damaged home in San Marcos, Texas, May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

Rescue personnel search the floodwaters along Brays Bayou in southwest Houston, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Daniel Kramer 

Flood waters cover cars at the Meyergrove Apartment complex in Houston, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Daniel Kramer 

James Canchola makes light of his flood damaged belongings while talking with friends outside of his home in San Marcos, Texas May 26, 2015. Torrential rains have killed at least 10 people in Texas and Oklahoma, including three in Houston where floods turned streets into rivers and led to about 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

Bill Taylor helps clean and remove debris from the interior of a friend's flood damaged home in San Marcos, Texas May 26, 2015. Torrential rains have killed at least 10 people in Texas and Oklahoma, including three in Houston where floods turned streets into rivers and led to about 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

A rescue worker scans a flooded area in south Houston, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Daniel Kramer 

Motorists block the offramp and share knowledge as flood waters cover areas in southwest Houston, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Daniel Kramer 

An uprooted tree sits in an open lot just beyond the banks of the Blanco River in San Marcos, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa 

Flood waters cover the intersection of Braeswood Blvd and the I-610 frontage road in Houston, Texas May 26, 2015. Torrential rains have killed at least eight people in Texas and Oklahoma, including two in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Daniel Kramer 

John Hansen checks his phone while he and friends work to remove damaged drywall and clean his flood damaged home in San Marcos, Texas May 26, 2015. Torrential rains have killed at least 10 people in Texas and Oklahoma, including three in Houston where floods turned streets into rivers and led to about 1,000 calls for help in the fourth-most populous U.S. city, officials said on Tuesday. REUTERS/Tamir Kalifa