It was early winter, and Department of Natural Resources Wildlife Technician Brad Johnson of Baraga was taking part in an aerial survey over Keweenaw Bay looking for wolf tracks, when he noticed a large dark area in the middle of the frozen bay. But Johnson's focus was on his wolf research, so he didn't give the ice much thought.

About two weeks later, he and his buddy, Dean, tested the ice near shore and, finding it to be a solid 4-5 inches thick, decided it was safe to go fishing. They hopped on Dean's snowmobile and balancing a pair of portable ice tents between them, off they went with Johnson holding a five-gallon bucket containing jigging rods and tackle in each hand.

"There was deep snow so it was impossible to tell how thick the ice was," Johnson said.

But they kept going out toward the 250-foot water depth where the fishing had been good the previous winter.

And, unknowingly, they rode right smack onto that dark spot in the ice that Johnson had seen from the plane.

"We were watching our landmarks and, about one-and-a-half miles out, we came to our fishing location," Johnson said," but as Dean slowed the snowmobile, the back end, where I was sitting, suddenly dropped through the ice, throwing me back into the frigid water."

Surprised, Johnson let go of one of the buckets as he fell, but as he went into the water the other filled quickly and the weight began taking him under.

"I knew I shouldn't panic, but the extreme cold took my breath away," Johnson recalled. "I let go of the bucket and eventually clawed my way out. Once out of the water, I rolled slowly away from the hole."

Johnson was soaked to the skin, Dean was wet to his knees and the snowmobile was precariously balanced on thin ice. The wind was pushing a 20-below-zero windchill.

"We grabbed what was left of our gear, but it was not safe to get the machine back to solid ice, so our only option was to walk back to shore," Johnson said.

By the time they gained solid ground, Johnson's clothes were so frozen they had to light a fire in his sauna and thaw them before he could take them off.

"After we changed clothes, we got some survival gear from the fire department and went back for the snowmobile," he said.

But it was too late. The snowmobile had gone to the bottom of Keweenaw Bay.

"I didn't tell my family about the incident, but they found out," Johnson said. "They gave me a set of ice picks, which I now carry around my neck every time I go out on the ice."

What else did he learn?

"Early ice is highly unpredictable, especially in areas where there is a lot of current. Now, when we go out those first few times, someone always walks in front of the snowmobile and checks the ice depth frequently," he said.

Johnson's experience is mirrored across the state each winter. He was fortunate.

Ice fishing has its own set of safety rules that if not followed, can cause a day of fishing to end in tragedy.

The strength of ice is determined by its look and texture. Clear ice is the strongest. Ice formed by melted and refrozen snow appears milky and is very porous and weak.

Ice covered by snow should always be presumed unsafe, because snow acts like an insulating blanket and slows the freezing process. Ice under the snow can be thinner and weaker. A snowfall also can melt existing ice, or push the ice surface down, causing water from beneath to well up over the top, creating a troublesome layer of slush. If there is slush on the ice, stay off.

The DNR also does not recommend the standard "inch-thickness" guide used by many anglers and snowmobilers to determine safe ice, because ice seldom forms at a uniform rate. Three or four inches of ice on a shallow farm pond with no inlets or outlets cannot be compared to the same amount of ice formed over a river with a strong current.

On big lakes, ice in some spots may be thick enough to safely hold a car while other areas may be little more than an inch thick. Be especially careful around pressure cracks.

The best way to ensure your safety is to always assume that no ice is safe. In addition, the DNR offers the following tips and safety guidelines for walking or fishing on the ice:

• Before venturing out onto the ice, check with local sources for the most up-to-date information on ice conditions.
• Always fish with a buddy whenever possible and always tell someone where you are going and when you expect to return.
• Do not go out on any ice unless you test the thickness and quality with a spud first.
• Avoid areas where there are inlets or outlets due to moving water under the ice.
• Avoid areas where there are natural springs.
• Avoid the ice around structures, docks and pilings.
• Pay attention to wind direction especially when fishing on large bodies of waters. If the wind direction is just right, it can blow the ice out and away from shore leaving anglers stranded.
• Wear a personal floatation device. Also, carry a couple of large nails and a length of nylon rope. If you should go through the ice, the nails could help provide a grip on the slippery surface and aid in getting you out.
• If you do break through the ice, try not to panic. Remember to turn toward the direction you came from -- toward the ice that supported you. Use the nails or your hands to gain a hold on the unbroken surface as an aid in getting out.
• Once you are out of the water and are lying on the ice, don't stand. Roll away from the point where you broke through until you are on solid ice.
• If you see someone fall through the ice, do not run toward the person. Carefully extend a rope, ladder, pole or line to the victim.
• Always get the victim to a hospital emergency room as soon as possible for treatment.

"We showed a lack of good judgment the day we went through," Johnson said. "We were lucky. Now my kids carry spuds and check the ice often, because that is what I do and they can see that I am now practicing what I preach."