High Cirriform Clouds Are Composed Almost Entirely of Ice Crystals

True/False

High cirriform clouds are composed almost entirely of ice crystals. In tropical regions, air temperatures low enough to freeze all liquid water usually occur only above 6,000 m (about 20,000 feet). In polar regions, however, these same temperatures may be found at altitudes as low as 3,000 m (about 10,000 feet). Hence, while you may observe cirrus clouds at 3,600 m (about 12,000 feet)over northern Alaska, you will not see them at that elevation above southern Florida.