(CNN) -- Two 18-month-old twins drowned after their mother tried to fend off a bee and let go of their stroller, which rolled into a canal, Arizona police said.
Alexis Keslar was walking with her twin sons, Silas and Eli Keslar, along a canal in Yuma on Friday when she tried to repel a bee, police in Yuma said.
"The stroller rolled away from her into the canal, with the boys belted in the seat," police said Monday.
Keslar went into the canal and tried to rescue her sons, authorities said, but was hampered by the steep sides of the canal, the depth of the water and the force of the current. The current washed the stroller away.
After Keslar got out of the canal, she called for help, police said.
The irrigation district that manages the canal slowed the flow of water and reduced the water level to help emergency workers find the boys, authorities said.
After more than an hour of searching, the toddlers were found and flown to a hospital, where they were pronounced dead.
"No parent should ever have to lose a child, you know, let alone both of them at the same time," family friend Marlene Gleim told CNN affiliate KYMA. "That's what really, really is heartbreaking to me, because those little boys were, you know, meant so much to so many people."
Authorities say the paths along Yuma canals are popular for joggers and bicyclists, but they can be dangerous.
"Many people typically do not comprehend how swift the current in these canals are and how deep the water can be," Yuma police said. "They also do not realize how difficult it is to climb back up many of the canal embankments."