Summer has rolled into this Montana town. The mercury is soaring, the air thick with haze.  Kids on street corners sell lemonade and Otter Pops; families flock to the swimming hole to float the afternoon away.  Some days, like today, are graced with an afternoon thunderstorm; temperatures drop 25 degrees in an instant and the wind carries the heady scent of pine and rain.  Plants drink up every last drop, as if they know the storms will become ever less frequent as the season