CONCORD — With the Meredith Rotary Ice Fishing Derby just days away, state wildlife officials are warning people to use caution before venturing out on lake ice.

A recent aerial survey of Lake Winnipesaukee found ice cracks that were pulling apart, river-like strips of open water and treacherous ice conditions, according to the New Hampshire Fish and Game Department.

Fish and Game Lt. James Goss urged people to not drive vehicles onto the ice because of unpredictable conditions. People on foot should test ice thickness with a chisel or auger.

“Many areas that have traditionally been safe for ice anglers and other outdoor recreationists are not safe this year,” Goss said. “We are urging people to use the utmost caution before you go out onto any frozen waterbody.”

Fish and Game noted that large lakes and susceptible to the high winds and above-normal temperatures of this winter.

On Feb. 4, the New Hampshire Civil Air Patrol snapped photos of Lake Winnipesaukee. They show river-like strips of open water running from the south tip of Rattlesnake Island both east and west completely across the lake. Open water could be observed northeast of and southwest of Rattlesnake Island.

In the “Broads,” numerous cracks appear to have separated, revealing open water. Another long opening in the ice runs from Welch to Lockes Island, and there are some areas of open water in the bay formed by the end of Moultonboro Neck, Timber and Governors Island. 

Ice safety tips:

-- Make sure there is 6 inches of hard ice before individual foot travel, and 8 to 10 inches for snow machines or all-terrain vehicles.

-- Weak ice forms when warming trends break down ice, then the slushy surface re-freezes. Be especially careful of areas with current, such as inlets, outlets and spring holes.

-- Stay off the ice along the shoreline if it is cracked or squishy. Don't go on the ice during thaws.

-- Watch out for thin, clear or honeycombed ice. Dark snow and ice may also indicate weak spots.

-- Small bodies of water tend to freeze thicker. Rivers and lakes are more prone to wind, currents and waves, which weaken ice.

-- Don't gather in large groups or drive large vehicles onto the ice.

-- If you do break, move or swim back to where you fell in, where you know the ice was solid. Lay both arms on the unbroken ice and kick hard. This will help lift your body onto the ice. Roll away from the hole until you reach solid ice.

-- A set of ice picks can help you pull yourself out if you fall through; wear them around your neck.

-- Snowmobilers should ask about trail conditions at local snowmobile clubs or sporting goods shops before they go onto ice.