Balmy weather, strafing winds and fluctuating water levels each inject uncertainty in the equation of when you can break out your ice auger, jigs and ice flies.
But a handful of big lakes in the region offer consistent early ice, generally growing a safe cap by Christmas.
The bonus is that each of these waters also features big, abundant trout. And the early ice season can be along with the ice-off bite the best time of year for steady action on trout, which are still energized by plenty of oxygen and food under the freshly frozen surface.
Most of these big-fish lakes have a few common elements: their location in high-elevation valleys which brings early freeze-up, varied forage ranging from aquatic insects to crayfish to minnows, and management that limits angling pressure for trophy fish.
Early-season ice fishing is similar on each of these lakes too. Most anglers use relatively small, natural-looking lures on light line, and they go easy on the bait.
In the early season, when the water is still clear and fish are still active, it's finesse presentations with marabou jigs, stonefly and mayfly imitations and small dark-colored ice flies that take the larger, more wary fish. That's not to say that big, garish spoons and jigs won't work they will but you'll catch more fish if you start small and work up in size and across the color spectrum.
Here's a thumbnail guide to catching big ice-bound trout in the Rockies before you have to break for Christmas obligations:
Georgetown Lake, Mont.
This 6,000-foot-high lake west of Anaconda produces plenty of beefy rainbow trout and cigar-sized kokanee every winter, and big-fish anglers occasionally take brook trout in the 4 to 5-pound class. But George-town, located along Highway 1 on the way to Philipsburg, can be maddeningly cyclic in the winter.
The most consistent approach is to jig with a two-lure rig, attracting kokanee with a deep glow-in-the-dark spoon or jig and a shallower Zonker or Double Bunny streamer baited with mealworms for the trout.
Head out from the Pumphouse for good mid-December ice, or walk on from Stuart's Landing.
Call Hardware Hank (406-563-7851) in Anaconda for updates.
Canyon Ferry Reservoir, Mont.
All you really need to use on this big Missouri River reservoir south of Helena is a black beadhead Woolly Bugger and a jar of maggots.
Early ice anglers use a wide variety of jigs, but a simple Bugger is effective for rainbows in the 2- to 4-pound class.
But early ice can be iffy here. Head to The Silos access off U.S. Highway 287 and then head south toward the mouth of the Missouri. This is the first part of the lake to freeze and it's also home to large December trout.
To save yourself a trip, call The Silos RV Park (406-266-3100) north of Townsend, Mont., to verify ice conditions.
Then bring a selection of those Buggers, preferably with a little glittering tinsel in their tails. You'll want to fish them fairly shallow, just about 4 or 5 feet under the ice in 15 to 20 feet of water.
Daniels Reservoir, Idaho
This southeast Idaho trout factory is finally back on line after losing a couple of seasons to low water. And it can be a great spot for both quick action on mid-sized trout and a shot at a whopper in the 18 to 21-inch class.
Stick to the shallow water habitats along the shoreline for good ice and fast action using a variety of neutral-colored jigs and flies, said Jimmy Gabettas at Jimmy's All Seasons Angler (208-524-7160) in Pocatello, Idaho. Even small midge imitations will work for early-winter rainbows here.
Daniels is located on the Little Malad River west of I-15. Take the Upper St. John Road out of Malad to Elkhorn Road and eventually the reservoir.
Lake Hattie, Wyo.
This lake west of Laramie on the Laramie Plains caps early, but it can reopen on short order with whipping winds. Still, it's at its best under December's ice, when ice anglers catch a mixed bag of rainbow, brown and lake trout.
A simple worm or maggot-baited curly-tailed jig will work for every fish in Hattie, said Randy Halvorsen at West Laramie Fly Store (307-745-5425) in Laramie, Wyo., and yellow is a good all-around color.
Halvorsen reminds anglers to prep for the store's annual New Year's Day ice fishing derby.
Best spot for rainbows in the 14 to 17-inch range is either along the south shore or off the face of the dam. Brown trout tend to go deeper and aren't a significant fishery in the winter. Neither are lakers, which average about 5 pounds and can be caught on larger jigging spoons baited with a wad of maggots, cutbait or a nightcrawler.
Strawberry Reservoir, Utah
The granddaddy of all big-trout fisheries in the Rockies, Strawberry's shorelines and bays freeze early, though the main-lake ice can be treacherous well into January, especially over the deeper water of the Soldier Creek Arm.
This could be a very good winter for big trout on the lake just off U.S. Highway 40 southeast of Heber City, said Alan Ward, the biologist assigned to Strawberry.
"About 20 percent of the cutthroats we caught in our spring gillnet surveys were over 20 inches long, and some rainbows in the 17- and 18-pound class were caught in the spring," he said.
"Opportunities are available for a large trophy fish."
Ward credits Strawberry's regulations that protect all cutts in the 15 to 22-inch class with the surge of big fish.
The best way to catch them is with a pink or orange jigging spoon or a gently jostled marabou or Foxee jig or leech imitation.
You can call Strawberry Bay Marina (435-548-2261) for on-the-scene ice reports.
Scofield Reservoir, Utah
This central Utah reservoir sits at more than 7,600 feet in a high Wasatch Mountains basin, but it's more productive than many low-country lakes.
The main catch here is planter rainbows (about 500,000 are stocked each year).
Rainbows average 15 inches, and late-fall anglers reported catching rainbows in the 17- to 20-inch class, said Paul Birdsey, aquatics manager for Utah's Division of Wildlife Resources.
The lake also has fair numbers of cutthroat, and tiger trout were introduced to Scofield a year ago, so they should be available to ice anglers this winter.
The go-to early ice hardware includes smaller brown, olive and black marabou jigs that imitate damselfly nymphs and other aquatic insects, said Ryan Stokes at Anglers' Inn (801-466-3921) in Salt Lake City, but he said that orange PowerBait is a good all-seasons attractor.
Good early-season spots are the east shoreline and the bay on the southwest shore out to the island.
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