Early one spring, the head guide at a fishing lodge on Colorado's West Slope asked a friend and me to help him scout some area lakes. He wanted to see how the fish had held up before his first clients arrived, and he needed a couple of extra rods to cover the water. There was a set of large ponds strung up a narrow valley that didn't get much sun. They were still half frozen, but the trout were lying along the ice shelf as if it were an undercut bank. The trick was to drop a weighted Woolly Bugger within an inch of the lip, let it sink for a count of five, and begin a slow retrieve. These rainbows were between 18 and 22 inches, they were hungry, and they hadn't been pestered for six months. It was almost too easy.
Of course, the fishing isn't always that hot when winter is melting into spring, but spending some time doing early-season scouting gives you a head start. The more fishing you do in less than ideal conditions, the more you'll learn about trout and about your own region, and that will make you a better fisherman. In every area where trout live, there are a few good early-season bets. Spring creeks have more uniform water temperatures, so they'll probably be open and fishable sooner than the surrounding freestone streams. The same goes for tailwaters, since streams fed by bottom-draw dams function as artificial spring creeks. Early fishing in spring creeks and tailwaters can involve a lot of nymphing, but hatches sometimes come off ahead of schedule in the warmer water, especially those of small aquatic insects like midges and the miniature, drab mayflies that flyfishermen call bluewing olives.
One advantage spring creeks have over tailwaters is that, although their flows do change, they usually fluctuate gradually. Water levels below dams can increase suddenly and drastically, and I'm convinced that it can take several days for trout to adjust to the higher water and start feeding again. Check the stream flows before you head out, and try to go when water levels have been stable for a few days. In the coldest weather, spring creeks and tailwaters will probably fish better close to their sources than they will miles downstream.
Watch the Mercury
The water in spring-fed ponds and lakes also tends to stay warmer than in those without springs (which is why the ice on them is seldom safe to walk on, even in the dead of winter), and they'll usually be the first bodies of still water to thaw. It's not always clear which lakes are spring-fed and which aren't, but one that has a slushy end or a corner of open water when every other lake in the neighborhood is frozen solid is a good bet. Of course, spring-fed lakes share the same advantage as spring creeks and tailwaters: Their stable temperatures and rich water chemistry increase both their growing season and their biomass, so they're capable of growing some very large trout.
Because weather conditions change rapidly with the seasons, you should always pay close attention and react quickly to weather-related opportunities. For instance, here in northern Colorado we get periodic late-winter thaws that can warm the water in streams just enough to get the trout biting. (If the water is already in the high 30s, a few degrees will do it.) These warm spells are sometimes accompanied by strong, warm chinook winds that can push the already thinning ice off of lakes that might otherwise have stayed frozen for another few weeks.
Naturally, a lake in a meadow in full sun will probably thaw sooner than one in a deep, shady forest; a stream on the south slope of a mountain will have more active fish sooner than one on the north side. It's true that a lot of early-season fishing will be marginal, and that's probably the best way to anticipate it: You'll get out, have a look around, and maybe catch a fish or two that you wouldn't have caught if you'd stayed home. But now and then, the fishing will be at its bestt at the ragged edge of the season. Maybe it's because the fish are excited by the first real hatch of the year, or they haven't been pounded into wariness by the mobs of fishermen that will arrive in another month. Or maybe it's that the water you're working wasn't fished by someone else just an hour before.
The great early days are impossible to predict, but one thing is sure: You'll miss them if you don't go fishing.
Test the Waters
Experts contend that if the water is colder than 44 degrees, trout metabolisms are too slow and they won't feed. It's a good rule of thumb, but if you've gone somewhere only to find the water still a little too chilly, fish for an hour anyway. I've caught too many trout from 39-degree water to take that 44-degree mark as gospel. Pictured: Orvis Stream Thermometer ($12; www.orvis.com).