Video: What is a Squall Line?

Squall lines are common during the spring and summer months. But what is a squall line? This video explains the core concepts behind this weather phenomenon.

What is a squall line?

A squall line is a line of strong and severe thunderstorms common in the spring and summer and often produce strong winds, lightning, heavy rain, and hail. Squall lines typically form along the leading edge of a strong cold front, where there is a sharp temperature difference ahead and behind the front.

A squall line is easily identifiable on radar by a long stretch of stronger returns, typically colored orange and red on most radar images.

What Weather to Expect

Tornadoes are not common in squall lines, however, there is an increased risk for severe straight-line winds as they pass. Large hail is also quite common in squall-line thunderstorms. Intense and continuous lightning is also a danger.

If a squall line approaches:

• If possible, seek shelter inside a sturdy building away from windows and doors.
• Avoid being outside.
• If you are driving, stay in your car and pull off the road.
• Be alert for flash flooding.
• Have a way out if need be.