An estimate of 20 girls remained missing after deadly flooding caused “destructive” floods at Camp Mystic in Hunt, Texas, Lt. Gov. Dan Patrick said.

Camp Mystic, a private Christian summer camp for girls, had to be evacuated overnight after “catastrophic” flooding along the Guadalupe River.

Rescue operations are ongoing in Central Texas after flash flooding along the Guadalupe River left 23 girls from Camp Mystic unaccounted for. Officials say dozens have died as catastrophic floods continue to ravage the Hill Country.