PIKE COUNTY, Ind. – Two southern Indiana children, a boy and a girl, have died after falling through thin ice.

Investigators don’t know why the two, both 12, were out on the frozen pond Thursday afternoon and the case is still under investigation. 

An Indiana Conservation Officer Public Safety Diver was able to rescue both children from the water, the first within 20 minutes of arrival and the second within 40.

It was estimated both children had been under water at least half an hour before being rescued. Both were taken to Memorial Hospital in Jasper for treatment where they died of their injures.

Much of the U.S. is being hit with extremely cold weather this past week and temperatures are not expected to raise in the next few days, according to the weather channel. States that rarely see ice are experiencing temperatures below freezing.

It is recommended by the Department of Natural Resources to have at least 4 inches of ice to support the weight of a person and to always wear a life jacket. To estimate ice thickness, pay attention to its color.

According to the Red Cross, clear blue ice is the strongest, opaque white is roughly half as strong and grey ice, which indicates unfrozen water, is the weakest. No ice should be considered safe ice.

Names of the children are being withheld until family has all been notified. Autopsies are scheduled for Saturday. No foul play is expected.

This story was originally published by the Washington, Indiana Times Harold.