We're in Yellowstone National Park on Monday. We follow the Madison as we leave the park.
Something is happening; cars are pulling over and people are jumping out with their cameras; a hapless cow elk is trying to cross the river.
My wife pulls over and I leap out with camera in hand glad to have the chance to check out another phenomenon I had noticed from the van: caddis are thick over the water, swirling in the breeze off a passing thunderstorm.
We leave the park, cut north, pick up I90 at Belgrade, and turn toward Missoula. We drive into the night.
On Tuesday morning in Missoula we see what we knew all along: that the rivers we passed or paralleled on the way--the Little Blackfoot, the Beaverhead, and the Clark Fork--had fine caddis hatches of their own.