Passage Summary: Global warming is going to turn mountain snow into rain, which means the water will rush down all at once in the spring instead of staying frozen until the summer when we actually need it.

Conclusion: Mountain snowpacks will likely melt faster and earlier, resulting in spring floods and summer water shortages.

Reasoning: Global warming will raise winter temperatures in the Rockies, causing more precipitation to fall as rain rather than snow.

Analysis: The argument relies on a causal chain: warmer winters lead to more rain, which leads to faster melting and specific water-flow problems. To strengthen this, we need to solidify the link between rain and the speed of the melt or the resulting water shortage. Look for an answer choice that suggests rain itself accelerates the melting of existing snow or that there aren't other factors (like increased total precipitation) that would prevent the summer shortage. We want to ensure that the shift from snow to rain is as damaging as the climatologist predicts.