The death toll from the July Fourth flash flood that ravaged a swath of central Texas Hill Country rose on Tuesday to at least 109, many of them children, as search teams pressed on through mounds of mud-encrusted debris looking for scores of people still missing, Reuters reported.

According to figures released by Governor Gregg Abbott, authorities were seeking more than 180 people whose fate remained unknown four days after one of the deadliest U.S. flood events in decades.

The bulk of fatalities and the search for additional victims were concentrated in Kerr County and the county seat of Kerrville, a town of 25,000 residents transformed into a disaster zone when torrential rains struck the region early last Friday, flooding the Guadalupe River basin.

The bodies of 94 flood victims, about a third of them children, have been recovered in Kerr County alone as of Tuesday, Texas Governor Greg Abbott said at a late-afternoon news conference after touring the area by air, according to Reuters.