Page 261 - NS-2 Textbook

256 NAUTICAL SCIENCES

2. Altostratus clouds are dense sheets of gray or hours. Spring ice storms, hurricanes, typhoons, or
blue, sometimes looking like ridges of frosted other severe storm conditions will generally ap-
glass, or flattened vapor trails. The Stm or Moon pear soon-even if the day when you see the par-
will glow dimly through altostrah,s, but without allel cirrus is beautiful and surmy.
a halo or corona. Light rain will probably occur 2. Cirrostratus clouds may nearly cover the sky with
within twenty-four hours. a ftlmy cloud. They often have a curly appearance
at their edges. Because they are made of ice crys-
High Clouds. High clouds are composed almost en- tals, these clouds form large halos around the Sun
tirely of tiny ice crystals. There are tiU'ee basic types:
and Moon. They indicate that clear and cold
1. Cirrus clouds are thin, wispy clouds composed weather can be forecast.
mainly of ice crystals. They are often called 3. Cirrocu111ulus clouds are thin, patchy clouds that
"mare's tails." In scattered patches, they normally often form in wavelike patterns. These clouds do
indicate cleat; cold weather. But if they are in par- not leave shadows on the Earth. Precipitation will
allellines across the high sky, it usually signals a usually follow them within twenty-four hours.
violent change in the weather within thirty-six
CLOUDS AT SEA

Clouds have been leading lost seamen, navigators, and ex-
plorers to land since the days of the earliest hardy sea voy-
agers. Fleecy white clouds on the horizon that are seem-
ingly stationary usually indicate that an island is close by.
Clouds form above islands for the satne reason that they

Altostratus clouds.

Cirrostratus clouds.

Cirrus clouds. Cirrocumulus clouds.