Floods of 1996 and 1997 Floods in Yosemite Valley aren't
uncommon during spring runoff, when the Merced River swells with
melted snow and overflows into meadows. The largest, least
common floods occur during winter--most recently in January
1997. See what Yosemite Valley looked like during the floods of
May 1996 and January 1997. (6 minutes) You can also download a
Quicktime version of this movie: [24 MB]. Did You Know? Natural
fires in Yosemite are often no more than a single burning snag
(standing dead tree) or a slow moving, low intensity fire that
cleans underbrush from the forest floor. These fires prevent
unwanted fires by removing accumulating forest debris that can
fuel a larger fire in hot, dry conditions.