Yosemite Nature Notes is a web video series that tells unique stories about the natural and human history of Yosemite National Park. This series features park rangers, scientists, historians and park visitors as they discuss the diverse plants and animals that make Yosemite their home, as well as the towering cliffs, giant waterfalls and mountain peaks that are known throughout the world. Summer visitors to Yosemite National Park miss many of the unique events of winter and early spring. Frazil ice flows are dramatic natural events that occur in the waterfalls of Yosemite Valley during March and April. These flows only occur on the coldest spring days, and despite their icy origins, they often behave just like molten lava!