Get a free trial until June 30, 2026!
New members get access to our science units, hands-on activities, mini-lessons, & more!

New members get a free trial through June 2026!
Back > Share
Back > Share

Where do flash floods happen?

Work of Water Unit
Lesson 4 of 6
Mapping & Severe Weather
4.8 (3934 reviews)
Lesson narration:
English Spanish
Scroll for prep
Video trouble?

DISCUSS:

Can you think of reasons why one place might flood more than other places?

Video trouble?

DISCUSS:

What is the ground like where you live?

Video trouble?

DISCUSS:

What could turn a puddle into a fast-moving river of water?

Video trouble?

DISCUSS:

How could you figure out which part of Texas gets the most flash floods?

Video trouble?

DISCUSS:

Imagine you're starting with a totally blank map of Texas.

What information would you want to add to your map to help you find Flash Flood Alley?

Video trouble?
Step
01/19
Find a partner — explorers often work in teams. You and your
partner will explore Texas together, share your ideas, and work
together to figure things out.
Video trouble?
Step
02/19
Get your supplies.
Video trouble?
Step
03/19
Cut the Flash Flood Finder worksheet in half on the dotted line.
Now each person has their own Flash Flood Finder.
Video trouble?
Step
04/19
Find the key on your map. It tells you what the marks on the map
mean. Find the waves in the key and on the map. Those waves mean
water. Color the area around the waves blue on the key and the map.
Video trouble?
Step
05/19
Find the numbers on the map that mark places where Flash Flood
Alley might be. If you find reasons that flash floods are likely at one of
these places, you’ll mark them on your Flash Flood Finder.
Video trouble?
Step
06a/19
Here’s the first clue to help you find Flash Flood Alley. Notice that the
parts of the map are different shades of gray. Look at the map’s key.
Discuss with your partner:
Video trouble?
Step
06b/19
The key shows the answer. Darkest gray is the highest land, where
there are tall mountains. Medium gray is lower land, where there are
hills, not mountains. Light gray is where the land is lowest.
Video trouble?
Step
07/19
These pictures show you what you’d see if you traveled to the
highest land, the lower land, and the lowest land on your map. Think
about what would happen in each place after a rainstorm. Discuss:
Video trouble?
Step
08/19
On your map, find where two shades of gray meet. In those areas, a
lower place is next to a higher place. Look for numbers nearby.
Because water runs downhill, flash floods are likely in those locations!
Video trouble?
Step
09/19
On the Flash Flood Finder's key, a triangle symbol means a lower place
is near a higher place. Draw a triangle by each number in a lower
place near a higher place. Flash floods are more likely in those places.
Video trouble?
Step
10/19
On your map’s key, find the line that marks where there are cliffs.
Draw an arrow to show water flowing down the cliff. Work with your
partner & draw arrows for water flowing down cliffs on your map.
Video trouble?
Step
11/19
Flash floods are more likely at the bottom of cliffs and rocky slopes.
On your map, look for numbers that are near cliffs. On your Flash
Flood Finder, put an arrow pointing down by those numbers.
Video trouble?
Step
12/19
On your map’s key, find the shape beside the words “Clay soil.” Use
your yellow crayon to color in the shape. Then find all the areas on
the map that have the word “clay” and color those areas yellow.
Video trouble?
Step
13/19
On your Flash Flood Finder’s key, color the square beside “clay soil”
yellow. On your map, look for numbers near areas with clay soil. On
your Flash Flood Finder, draw a yellow square by those numbers.
Video trouble?
Step
14/19
On your map’s key, find the symbol for “City.” The circle around the
dot shows the city’s pavement. Color the circle red. On your map,
make a red circle the size of the one in the key around each city.
Video trouble?
Step
15/19
On your Flash Flood Finder’s key, color the circle beside “pavement”
red. On your map, look for numbers near areas with lots of pavement.
On your Flash Flood Finder, draw a red circle by those numbers.
Video trouble?
Step
16/19
On the map, find four places marked with an X. Each X marks where
there was a giant rainstorm. Draw a blue cloud over the X in the key
and the Xs on the map.
Video trouble?
Step
17/19
On your Flash Flood Finder’s key, color the cloud beside “Giant
rainstorm” blue. On your map, look for numbers near the rainstorms.
On your Flash Flood Finder, draw a blue cloud by those numbers.
Video trouble?
Step
18/19
Now take a look at your map and your Flash Flood Finder.
Discuss:
Video trouble?
Step
19/19
Here’s what our Flash Flood Finder looks like.
Look at your map and discuss with your partner:
Video trouble?
Video trouble?
Slide Image
Slide Image

river


1 of 17

a long, thin area of water that flows
Slide Image

flood


2 of 17

an overflow of water

flash flood


3 of 17

an overflow of water that happens very fast
Video trouble?

rain


4 of 17

water drops that fall from clouds
Video trouble?

storm


5 of 17

weather that usually includes strong wind and rain or snow
Video trouble?
Slide Image

soil


6 of 17

tiny pieces of rock and other materials that cover the ground

sandy soil


7 of 17

a type of soil that has a rough texture; water easily flows through it
Video trouble?

clay soil


8 of 17

a type of soil that has a smooth texture; water does not easily flow through it
Video trouble?

absorb


9 of 17

to soak up liquid, like a sponge does
Video trouble?
Slide Image

cliff


10 of 17

a high area of land with a side that is almost straight up-and-down
Slide Image

hill


11 of 17

a high area of land that isn't as tall as a mountain
Slide Image

mountain


12 of 17

a high area of land with steep sides
Slide Image

slope


13 of 17

where one side is higher than the other
Slide Image

steep


14 of 17

something that is very high up on one end and very low at the other end
Slide Image

plains


15 of 17

large areas of flat land with few trees
Slide Image

map


16 of 17

a drawing of a place that shows where things are
Slide Image

model


17 of 17

a pretend version of something that scientists use when the real thing is too big, small, or complicated to work with
🎉 That’s it for this lesson! How did it go?

Extend this lesson

Vocabulary

Unit Reading

Assessments

View all extensions
Sign up now for more great lessons!
Sign up
Where do flash floods happen?
Work of Water Unit
Lesson 4 of 6
Mapping & Severe Weather
4.8 (3934 reviews)

Featured Reviews

“My students LOVED this lesson! They kept guessing throughout the lesson while they were filling out the Flash Flood Finder. It was lots of fun!”
· Theresa · Teacher
“I love the way the learning they have gained throughout the previous lessons, comes together to help them be science detectives and find Flash Flood Alley! ”
· Tracy · Teacher
“This lesson was the best yet! The kids were beyond excited to figure out where FFA was. They were very engaged. There was so much information and they learned every bit of it. AMAZING!!!”
· Jill · Teacher
“Seeing the pictures of the floods. We were curious about this topic! The activity was soooo fun.”
· Joan · Teacher
“My students were very engaged! It was interesting and the map was perfect for this age. My students wanted me to say: it was fun and like a treasure hunt. It was scientific. They are proud of their learning. ”
· Sarah · Teacher
“The directions were clear. The lesson was high interest. Students really understood the material.”
· Jane · Teacher
“Excellent step-by-step directions for identifying how to solve the question with repetition, visuals, aides, and an activity map. Loved the lesson!”
· Leticia · Admin
“Very informative and interesting. Loved the activity and so did the students. Thank you!!”
· Carol · Teacher
Lesson narration:
English Spanish

Activity Prep

Print Prep
In this lesson, students explore the phenomenon of flash floods and create an explanation of why these severe weather events are more or less likely in different regions. They specifically attempt to locate and explain a unique region in Texas known as Flash Flood Alley. In the activity, Find Flash Flood Alley, students develop a map to document how land and water interact across the state. Students then use that map to explain how different shapes and kinds of land increase or decrease the chances of rainfall causing a flash flood.
Preview activity

Vocabulary

Assessments

I have a Mystery Pack

Flash Flood Finder printout Print 15 copies
Texas Explorer Map printout Print 30 copies
Crayons
We suggest yellow, red, and blue crayons for each student. Colored pencils also work.
Details
90 crayons
Scissors
15 pairs
Prep Instructions

We suggest students work in pairs. Homeschool students can work on their own.

Standards

Jump to

Exploration

20 mins

Hands-On Activity

35 mins

Wrap-Up

5 mins

Share this lesson

Student link

Google Classroom

Email parents

Slow internet or video problems?
Credits
 
Water Lesson 4: Where do flash floods happen?

How did the lesson go?
Terrible OK Good Great Terrific!

How can we improve it?

If you'd like our team to reply to you, please Contact Support instead.

Thanks for your feedback! If you have a question or need help, please contact us. Please consider sharing your review:

Sorry the lesson didn't go well. We read every single review in an effort to improve our Mysteries.

Thanks for letting us know. We’ll wait to ask you for feedback until after you've actually taught it.

Thanks for the feedback! We read every single review in an effort to improve our Mysteries.

Is the video not playing properly?

Please follow these steps:

  1. Very rarely a video will fail to completely load in your browser. Try to reload this page to see if that fixes the problem.
  2. If reloading does not help, try our other video player .
  3. If the video still fails to play, open this video in a new tab and please let us know you’re having trouble. We want to fix this issue for you.

This episode is locked

This lesson is not included in your limited access.

View pricing

This episode is locked

Your membership is expired. The archive of past Mini Lessons is not included in your limited access.

View pricing