At least 104 people are dead after heavy rain led to devastating flooding in Texas. Kerr County was hit the hardest, with at least 87 deaths, including 30 children. President Donald Trump signed a disaster declaration for the county and the Federal Emergency Management Agency is on the ground there.

Here’s what to know about the deadly flooding, the colossal weather system that drove it in, and around Kerr County, Texas, and ongoing efforts to identify victims.