Ever since the West was settled, late fall and early winter snow would begin to pile up in the mountains. "But now, with higher temperatures, that precipitation ... is now falling as rain and running off right away." It does not contribute to the snowpack and is lost to human use. "The reverse is happening in the spring," with early warm weather reducing the snow accumulation.

"So the bottom line is we have shrinking snowpacks" and the seasonality of precipitation is changing, Wagner said.

Agricultural irrigation and hydropower electrical generation could be affected, he added. "And of course, we have domestic use of water, particularly in the summer when we're watering our lawns and our yards."

But what about the predicted increase in precipitation? Will that offset the changes in the runoff? Possibly yes, but it's still too early to tell, according to Wagner.

A series of new models have been drafted, he said, "and they're all over the map in predicting precipitation."

Wagner would like to see more study of possible changes in Utah's stream-flow. "We definitely need more research, no question on that."

---

E-mail: bau@desnews.com