•While summer
flooding is typical of the eastern Rockies, wintertime flooding is the greatest danger in the mountains along
the West Coast.
•Flash flooding in the river valleys of the Sierra Nevada,
cascade, and Coastal ranges
often leads to more widespread flooding in the larger valleys at the base of these ranges.
•For California, Pineapple Express bring the heaviest
precipitation, whose freezing level is high and most of the precipitation falls as rain in
the mountains.