Parts of Texas devastated by flash floods that left at least 89 people dead over the July Fourth holiday weekend braced for more heavy rains as forecasters extended flood warnings through Monday evening.

Flash floods in Texas have killed nearly 90 people, many of them children. Heavy rains fell quickly in the predawn hours Friday in the Texas Hill Country, causing the Guadalupe River to rise 26 feet in just 45 minutes.

Flash floods happen when heavy rains unleash more water than the ground can absorb, causing that water to pile up and flow to low-lying areas