Notes – Severe Storms
Hurricane
 It is a large rotating storm of tropical origin with sustained winds of at least 119 km/hr or 74 mph;
a very LOW pressure system
 EYE: extremely low pressure center of the hurricane; air sinks here, so no clouds & very calm
 EYE WALL: ring of violent thunderstorms around the eye; strongest wind & rain are here
 STORM SURGE: large wave of water caused by a low-pressure system
 WINDS: create large waves to damage coast & cause flooding
 Worst damage happens to RIGHT of hurricane in N hemisphere, because wind blows COUTNERCLOCKWISE
around the low, so the strongest winds are on the right
Saffir-Simpson Scale
Thunderstorms
 A storm with rain, lightning, and thunder, and sometimes hail and tornadoes.
Life Cycle
CUMULUS STAGE

MATURE STAGE
DISSIPATING STAGE
LIGHTNING: A discharge of electricity from a thundercloud to the ground, from cloud to cloud, or within
the cloud
Nor’easter (North-easter)
 a low pressure system along East coast that blows strong winds from the northeast; not cold enough to be
considered a blizzard, but very strong winds & damage
Blizzard
 a winter storm with high winds,
low temps (< -7oC )
Tornado
 A violent, rotating column of air that extends down from dark clouds and moves over land in a narrow,
destructive path.
TORNADO WATCH: indicates that conditions are right for a tornado to develop and that the sky should be
watched. Be alert to changing weather conditions!
TORNADO WARNING: indicates a tornado has been sighted or that radar indicates one has developed or could
develop within minutes. Warnings will give the location of the tornado and the area immediately affected by
the warning. When a warning is issued, move quickly to shelter!