A woman was swept out to sea and drowned at a California beach after she helped to save three children during a trip, authorities said Monday.

Aarti Senthilvel, 47, of Pleasanton was visiting the beach south of San Francisco with her family and two others when 11 of the children and adults were pulled into the water by the undertow.

Senthilvel helped save three children and teenagers, San Mateo County sheriff’s Detective Rosemerry Blankswade said.

“While they were attending to the children they didn’t realize she was taken by the undertow,” the detective said.

Emergency personnel arrived and pulled Senthilvel from the water but were unable to save her.

A relative said Senthilvel was known for helping others.

California State Parks Public Safety Superintendent Bill Wolcott said the waves were small on Sunday at Cowell Ranch State Beach near Half Moon Bay about 30 miles (50 kilometers) south of San Francisco.

However, ocean currents always pose a risk, he said.

“Cowell Beach is definitely infamous for this type of current, and we want to remind everybody with the holiday coming up to be safe,” Blankswade said.

Senthilvel’s death followed three similar incidents last month in which people drowned or nearly died while rescuing children in the state.

A father and daughter drowned in the San Joaquin River, the Visalia Delta Times reported .

Another person drowned and one nearly died trying to rescue children from the Kaweah River, about 170 miles (270 kilometers) north of Los Angeles.

Days later, a 7-month-old boy was rescued. His rescuer survived but was seriously injured.

In early June, a 36-year-old Los Angeles man drowned in the same rapids.

(AP)