Amid staggering loss, hundreds gathered in mourning and prayer at a Wednesday night vigil for the victims of the July Fourth floods.

A flash flood is a rapid rise of water along a stream or in a low-lying urban area, the National Weather Service said. Flash flooding can result from slow-moving thunderstorms, from numerous thunderstorms that develop repeatedly over the same area, or from heavy rains associated with tropical cyclones.

Here's what to know about the deadly flooding, the colossal weather system that drove it and ongoing efforts to identify victims.

When the precipitation intensified in the early morning hours Friday, many people failed to receive or respond to flood warnings at riverside campsites known to be in the floodplain.

The event was held as search crews and volunteers continued to scour miles along the Guadalupe River for the people still missing.

Eight-year-old girls at sleep-away camp, families crammed into recreational vehicles, local residents traveling to or from work. These are some of the victims.

FEMA staff have also been answering phones at a disaster call center, where, according to one agency official, callers have faced longer wait times as the agency awaited Noem’s approval for a

Kerr County officials say they are still focused mainly on the search for survivors with hundreds still missing and weren't yet examining how the emergency response unfolded.

An 8-year-old girl who aspired to play the lead in an upcoming camp production is among the latest victims of the flooding in Texas.

The first weather emergency alert sent by the National Weather Service with urgent language instructing people to "seek higher ground now" was sent at 4:03 a.m. local time.

Throughout the Green Mountain State, residents are still reckoning with the damage inflicted by seven federally declared major disasters over the past two years — and casting a wary eye on President Trump's plans to shrink FEMA.