Heavy rains fell quickly in the predawn hours of Friday in the Texas Hill Country, causing the Gaudalupe River to rise 26 feet in just 45 minutes.

The death toll from catastrophic flooding in Texas rose to more than 100 on Monday, as rescuers continued their grim search for people swept away by torrents of water.

Catastrophic flooding struck central Texas on Friday as the Guadalupe River surged by more than 20 to 26 feet within 90 minutes, causing widespread devastation and forcing mass evacuations in Texas Hill Country. At least 80 people have been killed in the floods while others remain missing or displaced and more than 850 people required rescuing.

A hydrologist explains why Texas Hill Country is known as Flash Flood Alley and how its geography and geology can lead to heavy downpours and sudden, destructive floods

Walmart, Sam’s Club and the Walmart Foundation are committing up to $500,000 to support Texas flood relief efforts. This includes up to a $250,000 match of customer and member donations, that can soon be made online or in-stores and clubs in Texas, through the Walmart and Salvation Army match campaign.

Shakira is reaching out to help the victims of and families devastated by the ongoing floods in central Texas. “Dear San Antonio, Our hearts and prayers are with those affected by the flood in Central Texas,