By: Hannah Jorgensen

Upper Lever Clouds

High clouds must be higher than 6 kilometers. They are thin, white clouds composed of ice. They have small amounts of water vapor and have low temperatures at high altitudes.

Cirrus, Cirrocumulus, Cirrostratus

Middle Level Clouds

Middle clouds form between 2 and 6 kilometers. They are composed of liquid water. Altocumulus clouds indicate settled weather. Altostratus clouds are associated with changing weather.

Altostratus, Altocumulus

Lower Level Clouds

Low clouds occasionally occur as individual clouds, but usually appear as a general overcast and are associated with somber skies and drizzly rain.

Stratocumulus, Nimbostratus

Vertical Clouds

These are the low bases to heights of as much as 15 kilometers. They indicate very active vertical movement in the air.

Cumulus, Cumulonimbus


Fog is clouds on the ground. It forms in four different ways.

Radiation Fog: When the ground loses heat through radiation usually at night. As heat radiated away from the ground passes through lowest layer to higher area the air closest to the ground cools as heat flows to the relatively cool ground and fog condenses in the cool air at the dew point.

Advection Fog: When warm moist air moves horizontally over a cold surface such as snow-covered ground or a cold ocean current.

Upslope Fog: Created adiabatic cooling when humid air climbs a topographic slope

Evaporation Fog: Water vapor is added to cold air that's already near saturation.

Joplin, Missouri Tornado

When? Where?

The EF-5 tornado hit Joplin, Missouri on May 22, 2011.


It all started with the above average temperatures in the Gulf of Mexico. The warm moist air from the Gulf met cooler, dry air coming down from Canada in the Midwest and all of Tornado Alley. It was said to be a very storm in the beginning, coming down from the Pacific Coast, across the California highlands, over the Rocky Mountains, then took a turn for the worse and headed towards the Central Plains where it met the strange combination of the cold, dry air and the warm moist air creating disaster. It started as huge thunderstorms sending rain and hail, then turned into tornadoes in other cities and states before it hit Joplin. A low-lying wind from the south began blowing hard and the atmospheric instability went through the roof. A supercell that formed in Kansas grew so much that two new supercells formed leaving three with a path of destruction. Then a fourth cell formed. Two of them merged near the border of Kansas and Missouri and began spinning rapidly only one to two miles above ground. The tornado sirens blew around 5:31. A few short minutes later, the tornado touched down, winds coming around 200 to 300 mph and was almost a mile wide. It left a path of over 22 miles long, destroying everything in its path.


Around 7,000 homes were destroyed in a matter of 38 minutes, not including businesses or other public buildings. The St. John's Hospital was severely damaged, and the Franklin Technical Center and Joplin High School were both destroyed.


There were 158 fatalities making it the seventh deadliest tornado in U.S. history. Along with the 158 fatalities, over a thousand other people were injured from the storm.