Police were out on Lake Simcoe on Friday looking for some of the biggest dangers at this time of year…pressure cracks.

CTV News was onboard of the York Regional Police (YRP) airboat on Friday as they did their daily check of the ice.

Keeping an eye on the ever changing conditions can be tricky. New, fresh snow is always an issue. Even blowing snow poses problems and police want people to know there are several new cracks out on the ice.

“Right now there are big pressure cracks, bigger than we’ve had in years,” says YRP Constable David Flood.

Police are particularly concerned because of the wild weather changes. They fear people not familiar with ice safety may make a deadly mistake.

“Ice will react to the temperature; it will contract when it’s cold and expand when it’s warm. So on a mild day like yesterday where we saw temperatures -2 or -3, the two sheets of ice would hit each other and pile straight in the air and we got very pronounced and very tall cracks,” adds Flood.

Police say people driving their vehicles out on the ice are taking their chances. Even though there is plenty of thick ice, they are just as many thin spots.

While there is technically no speed limit on the ice for vehicles, police are pleading with people to slow it down.