The Kerrville Police Department has suspended ground search operations due to the current flood danger.
"We will provide more information soon but for now, all search crews need to evacuate the river corridor until further notice," police said in a statement Sunday morning.
Police said they are "seeing heavy rain in Kerrville at this time" and that volunteer operations are currently suspended "until further notice."
Highway 39 is also closed to "everyone except first responders and residents."
"Protecting lives is our highest priority," police said.
The National Weather Service issued an alert Sunday morning for "life-threatening flash flooding" in in Kerr and Gillespie Counties, including the areas of Kerrville, Comfort, Ingram, Hunt, Mountain Home, Waltonia, Harper, Kerrville-Schreiner Park and Cypress Creek. Up to 2 inches of rain have fallen in those areas, with rainfall rates expected to reach 1 to 2 inches per hour, the National Weather Service said.