Book 7, Question 61
Why Do Fronts Look Like Triangles and Semicircles?
A front is the boundary between two different air masses, one cold and one warm. On weather maps, fronts are drawn with a line and little shapes. Cold fronts get blue triangles, and warm fronts get red half circles.
From the book
Page from A Million Whys Book 7
More fun facts
- The triangles and half circles point in the direction the front is moving.
- A stationary front is a front that isn't moving. It is drawn with alternating red half circles and blue triangles.
- An occluded front is drawn in purple, with triangles and half circles on the same side.
- An occluded front usually means the storm system is mature and starting to weaken.
- Cold fronts nearly always stretch to the south and west of a low-pressure center.
- From space, a cold front can show up as a long, curving line of clouds.
Sources: NOAA, NASA Science
Questions kids ask
What does a purple front mean?
It is an occluded front, often a sign that the storm system is starting to weaken.
Which way do the triangles point?
In the direction the front is moving.