Ice can vary in thickness and is treacherous to walk on.

As the big freeze continues, many Irish people, unused to seeing lakes and rivers frozen over, are skating, walking and playing on thin ice, little realizing that they’re putting their lives in danger.

Both adults and children have been seen walking on ice in lakes in Cavan, Mullingar and elsewhere.

An engineer from Cavan, Kevin Sexton, told RTÉ’s News at One programme yesterday that people were indulging in “crazy behavior.”

Sexton said he had heard of people cycling on frozen lakes, and one of his co-workers saw an adult walking with two children across a lake earlier this week.

Sexton explained on RTE that ice can vary in thickness. “If people end up being on the ice at that stage they could end up going through it . . . Nobody wants to see a tragedy,” he said.

On Friday two brothers died after falling through ice on a frozen lake in Britain.

A Garda press office spokeswoman told the Irish Times: “Young children are skating on lakes and thinking that they are safe, but it could crack under them and they could get stuck underneath.

“We are urging extreme caution for children when outdoors to stay away from lakes and rivers because we don’t know how safe they are,” she said.

It is to be hoped that people heed the Garda warning. Sexton said earlier this week he saw someone pushing a person in a wheelchair across the ice on a lake.  “This is unbelievable,” he said.