ON THE GUNFLINT TRAIL – The recent cold that enveloped Minnesota's northern border bottomed out at 37 below zero, a temperature that would test the mettle of Pete Harris' blaze orange deer-hunting outfit. Fortunately, a heat wave had moved in and as we slid Pete's snowmobile off its trailer, the mercury drifted toward a more comfortable minus-7.

The goal was to fish lake trout through the ice.

Pete and his wife, Carol, live outside of Grand Marais within a stone's throw of Lake Superior, and if Pete wasn't fishing on this recent morning he'd be splitting wood or figuring out how, in the North Shore's deep snow, he'll get around in his sugar bush later this month.

He'll tap 80 maple trees, which is seven fewer than his age.

"I like the fresh air," he said.

The tall pines that surrounded us gathered their shape in the morning's first blush as we filled a weathered Duluth pack with sandwiches, minnows and other gear.

The side road we were parked along was bracketed by snow stacked preposterously high by ghost plows that work through the night, clearing paths for cabin owners, snowmobilers and wolves.

"I think we've got everything," Pete said, aiming the snowmobile for a trail leading to our destination lake.

Pete grew up in Cloquet, the son of a brook trout fisherman who with young Pete regularly angled up Hwy. 61, destined for the narrow streams that gather in the high country overlooking Lake Superior.

The Caribou and the Cascade were favorites, as was Two Island River.

"Every summer until my dad died at 87, we also made annual treks for brook trout farther up the North Shore, into Canada," Pete said. "Dad fly-fished wet with a dropper, and I fished dry. We either camped out or stayed in motels, cooking supper on the tailgate of our truck. When I got older, we'd smoke brook trout in the evenings to eat the next day for lunch."

Terry Arnesen had driven up with me from the Twin Cities and had gone ahead of Pete and me on snowshoes. Were this a summer day we might be fishing along the Gunflint for smallmouth bass or walleyes. But in winter the better option is lake trout or, alternatively, splake, whether from waters inside or outside the Boundary Waters Canoe Area Wilderness.

Duncan, Daniels and Ram are among BWCA lake-trout waters that can be reached fairly easily off the Gunflint on skis or snowshoes, while Greenwood, Trout, Kemo, Loon and Gunflint are among lakes outside the wilderness where trout are wintertime attractions, and where snowmobile travel is an option.

Amid the long shadows that bridge night and day we reached our chosen lake. In his mind's eye Pete saw not only the lake's broad frozen expanse but the trout that swam below. These fish, he said, move by dark and light between shallow water and deep, explaining why, after crossing the lake, we halted our little caravan on ice atop water only 10 feet deep.

Attempting to reach that water, Pete's auger nearly disappeared into its crystalline boreholes.

Noting the ice thickness, Terry said, "I guess it has been cold up here."

To block a stiff breeze that skimmed across the lake, we half set up Pete's portable shelter. Then Terry and I watched as Pete produced a small block of wood and a timeworn knife with a 4-inch blade.

"Lay the minnow on its side," he instructed — he used the wood as a surgical table — "and angle the knife edge toward the minnow's head. Then cut through the minnow diagonally just behind the dorsal fin and remove the air bladder. This keeps the minnow from floating up from your lure."

Within minutes each of us had affixed half-minnows to Northland rattle spoons and dropped them into the chilled water, watching as we did monofilament line spool stiffly from our small spinning reels.

Standing on one side of Pete, Terry turned his back to the wind and jigged his spoon and bait, while on Pete's other side I bent over an ice hole that froze shut nearly as quickly as I cleared it.

Minutes passed before without fanfare Pete reeled a laker onto the ice. This wasn't a big fish, but feisty enough and an ideal size for eating.

"Not as big as the ones you catch on Lake Superior," I said.

Pete and I first met last fall in Grand Marais when he showed me the 14-foot aluminum boat he uses in spring, summer and fall to fish lake trout on the big lake.

The two outriggers that swing from the boat's stern and one to starboard are telltale of his intent when, guided by a hand-held GPS and watching a small-screen depth finder, he departs the Grand Marais harbor a couple of times each week for the horizon beyond.

Pete bought the boat, a 1964 Starcraft, when he and Carol lived in Grand Rapids, where Pete worked at UPM Blandin for 32 years as a chemical engineer.

"After I retired and we moved to Grand Marais, I went out on Lake Superior with a charter boat captain to learn how to fish lake trout," Pete said. "I thought I could fish the lake in my 14-foot boat if I just used common sense."

Pete stashed his lake trout in a bucket to keep it from freezing and impaled a second minnow onto the small treble hook that swung from his rattling spoon.

Then he dropped the rig to within 8 inches or so of the bottom and jigged it there for enticement.

All the while he wore no gloves, and Terry wondered how, at going on 90 years of age, he had any fingers left.

"I suspect my hands didn't feel cold because the tips of my fingers were slightly frostbitten," Pete would explain later.

In the next hour or so, another eight trout were pulled through the ice, with still others evading our hook-sets.

"I can't believe we're catching them so shallow," Terry said.

"If we had been here earlier, we'd have drilled holes in even shallower water," Pete said.

When the sun crested the pines on the distant shoreline and rose into the morning sky, the bite tapered off.

We kept five of the trout — enough for the frying pan, and for the freezer, too.

By then the temperature had risen to zero degrees, or thereabouts.

Folding Pete's shelter into its sled, we stashed our gear and retraced our trail to the truck.

Soon the sugar bush would be calling, and Pete had to figure out how to get around in the North Shore's deep snow.