Like many bodies of water in Alaska, Big Lake becomes a snow machine super highway when it's frozen.

"We call it Ice-5," Dan Mayfield said, adding it's a play on Interstate 5 along the west coast. "This is our main winter highway and it's important for people who live on the lake and for commerce on the lake."

For 15 years, Dan and his wife Cathy have volunteered their time to take measurements along the ice road.

"I'm looking for the magic 12 inches. Basically that's good for a three-quarter ton pickup going across the lake," he explained.

The track the thickness every tenth of a mile. Dan uses a chainsaw to carve through and shouts the numbers to Cathy, who marks them on a map.

When most of the ice is more than a foot thick they'll plow a path for larger trucks. Until then, there's a bigger risk of falling through.

"Ice is never really safe. People need to make their own judgement if they want to get (onto) the ice or not," Dan said.

Sometimes it's hard to tell what's beneath the fresh coat of snow. On Friday, Dan found overflow in several spots off the main ice road.

"This is one of the danger signs on the lake: we can get overflow that's a foot or more deep," Dan explained. "People have trouble, they get their machines stuck, can't get them out."

Dan and Cathy Mayfield examine the overflow depth on Big Lake.

After they finished their final two miles, the ice looked thick enough for them to widen the road, but not fully open it just yet. It's not a decision the Mayfields make lightly following the search for missing snowmachiners LaVerne and Van Pettigen, which ended last weekend with their bodies being recovered from the lake.

"We take it as a grave responsibility to do this kind of stuff, because it means the difference between life and death in some cases, or losing your vehicle in the ice," Dan said.

There's a New Year's Eve fireworks show on Big Lake that always draws a crowd. Dan recommends people watch from the shoreline this year and advises spectators to avoid parking on the ice, which is likely not thick enough to support a large number of vehicles.

The Mayfields post their ice thickness measurements on their Facebook page, Big Lake Trails.

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