Spring is here. Visions of slashing rises and strained leaders fill your mind as trout waters begin to warm from a long winter. Anxious sub-surface insect life begins to stir as water temperatures gradually move toward that magic 53-degree mark.

Big rainbows like this are once again attacking caddis and stoneflies in prolific hatches in Colorado rivers around the state. Photo courtesy of Steamboat Flyfishers

Anglers also anxiously await reports of bug-filled clouds over the rivers. They pray that spring runoff will hold off as long as possible. Late April into May finds caddis fly masses hatching in what is often called the "Mother's Day" hatch. Colorado's Arkansas River is famed for its blizzard hatches. It attracts anglers from everywhere. This hatch is often so intense that fishermen can barely breathe. They mask their faces to avoid inhaling caddis.

Because of its renowned status, the Arkansas can be overrun with anglers during the hatch. The good news is many other Colorado rivers offer excellent caddis hatches for those who prefer to avoid crowds. Although the hatches may not always be quite as intense as the Arkansas, fishermen will still be greeted by hordes of willing, hungry trout gorging on the season's first meaty flies after a sparse diet of midges and blue-wing olives.

TIMING
Like the Arkansas, caddis revivals begin on the lower sections of rivers and move upstream daily.

Rising water temperatures that result from increasing daylight hours and sunshine seem to be the key triggers for the hatches.

At lower elevations, the "Mother's Day" hatch is usually over by Mother's Day -- washed out by heavy runoff. On higher rivers, depending upon conditions, the hatch may coincide with runoff or even occur as runoff begins to subside. In this instance, fish will hang along the banks and feed heavily.

If you're serious about catching the hatch, watch weather conditions closely and query local shops to determine river conditions and hatch status. If water temperatures are rising rapidly, it foretells an early runoff as well, so be prepared to get on the water.

HOW TO FISH THE 'OTHER' HATCHES
Aside from the Arkansas River, Colorado has major hatches on several rivers including the Roaring Fork, Colorado, Animas, Gunnison, Rio Grande and Eagle. These early caddis flies are followed by a continual parade of differing species throughout the summer into fall.

Roaring Fork River
Like the Arkansas, the spring caddis hatch on the Roaring Fork attracts both fishermen and big trout. While BWOs, pale morning duns, and green drakes receive the headlines, caddis are more numerous and serve as the mainstay trout food throughout the spring into fall.

A massive spring caddis (Brachycentrus Occidentalis) hatch kicks off the season in April beginning on the Colorado River below its confluence with the Roaring Fork at Glenwood Springs. Warming waters attract the newest caddis generation up this rock-and-roll freestone river rapidly until spring runoff hits bringing this spring renewal to a halt. Once the caddis arrive, be ready to go quickly -- it doesn't last long!

La Fontaine's Deep Sparkle Pupa and Emergent Sparkle Pupa combined with a variety of adult patterns should meet every need on the Fork. The April caddis is a dark fly matched by a No. 14-18 black or dark-gray pattern.

At times, the cloud of newly hatched caddis can become so thick they'll hinder your breathing. Avoid this by fishing just ahead or behind the blizzard where there is less competition for the trout's attention, and it is easier to see your offering.

If you find yourself caught up in the blizzard, you might try using a totally different fly pattern to make your fly distinct.

Colorado River
The spring caddis hatch on the Colorado River, especially in the Middle Park section, can be as dense as that of the Arkansas. It's probably the most dependable insect hatch on the river, too.