Floods
Chapter 17
Sections 2 & 3
Pages 567-582
Floods
• Are the most dangerous weather-related
events in the US.
• Floods occur when water pours into a
stream or river that it overflows its banks
and covers the land on either side.
Flash Floods
• A sudden, violent flood when water rises
very rapidly.
• Unexpected floods are the most
dangerous.
• It occurs within a few hours or even a few
minutes of a storm.
Predicting Floods
• Advanced warnings can help reduce flood
damage and loss of life.
• Weather satellites can supply information
about snow cover, so scientists can
estimate how much water will rush into the
river when it melts.
• Scientists check river gauges that
measure water levels.
Predicting Floods
• Forecasters can predict flood heights at
different points on the river with the goal to
help prepare people and evacuate.
• A flood watch- means that flooding is
possible.
• A flood warning- means that flooding has
been reported or is about to occur. Take
action!
Flood Emergency Safety
• First rule of flood safety- move to higher
ground and stay away from flood waters.
– Do not try to cross streams and rivers that
look flooded.
– Do not play in water.
• A few centimeters of water can sweep you off your
feet.
– Do not try to drive on a flooded road.
• Moving water can sweep a car away.
• Leave the car and move to higher ground.
Other Flood Hazards
• Floods can knock down electrical poles, wirescutting off power supplies.
• Can saturate soil, causing landslides or
mudslides.
• Emergency vehicles cannot get through flooded
roads.
• Flood waters can pollute water in wells and
water treatment plants.
– Be careful with anything that flood waters have
touched.
– Boil water before drinking it.
Storm
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